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Document and Entity Information - USD ($) $ in Millions	12 Months Ended
Document and Entity Information - USD ($) $ in Millions	Dec. 31, 2015	Feb. 16, 2016	Jun. 30, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Five9, Inc.
Trading Symbol	FIVN
Entity Central Index Key	0001288847
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Common Stock, Shares Outstanding		51,243,399
Entity Public Float			$ 103.6

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 58,484	$ 58,289
Short-term investments	0	20,000
Accounts receivable, net	10,567	8,335
Prepaid expenses and other current assets	2,184	1,960
Total current assets	71,235	88,584
Property and equipment, net	13,225	12,571
Intangible assets, net	2,041	2,553
Goodwill	11,798	11,798
Other assets	934	1,428
Total assets	99,233	116,934
Current liabilities:
Accounts payable	2,569	4,179
Accrued and other current liabilities	7,911	7,318
Accrued federal fees	5,684	7,215
Sales tax liability	1,262	297
Revolving line of credit	12,500	0
Notes payable	7,212	3,146
Capital leases	4,972	4,849
Deferred revenue	6,413	5,346
Total current liabilities	48,523	32,350
Revolving line of credit — less current portion	0	12,500
Sales tax liability — less current portion	1,915	2,582
Notes payable — less current portion	17,327	22,778
Capital leases — less current portion	4,606	4,423
Other long-term liabilities	582	548
Total liabilities	72,953	75,181
Commitments and contingencies (Note 11)
Stockholders’ equity:
Preferred stock, $0.001 par value; 5,000 shares authorized, no shares issued and outstanding as of December 31, 2015 and 2014	0	0
Common stock, $0.001 par value; 450,000 shares authorized, 51,165 shares and 49,322 shares issued and outstanding as of December 31, 2015 and 2014, respectively	51	49
Additional paid-in capital	180,649	170,286
Accumulated deficit	(154,420)	(128,582)
Total stockholders’ equity	26,280	41,753
Total liabilities and stockholders’ equity	$ 99,233	$ 116,934

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Preferred Stock, par value	$ 0.001	$ 0.001
Preferred Stock, shares authorized	5,000,000	5,000,000
Preferred Stock, shares issued	0	0
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$ 0.001	$ 0.001
Common Stock, shares authorized	450,000,000	450,000,000
Common Stock, shares issued	51,164,621	49,322,498
Common Stock, shares outstanding	51,164,621	49,322,498

Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenue	$ 128,868	$ 103,102	$ 84,132
Cost of revenue	59,495	54,661	48,807
Gross profit	69,373	48,441	35,325
Operating expenses:
Research and development	22,659	22,110	17,529
Sales and marketing	42,042	37,445	28,065
General and administrative	25,822	24,416	18,053
Total operating expenses	90,523	83,971	63,647
Loss from operations	(21,150)	(35,530)	(28,322)
Other income (expense), net:
Interest expense	(4,727)	(4,161)	(1,080)
Interest income and other	100	245	29
Change in fair value of convertible preferred and common stock warrant liabilities	0	1,745	(1,871)
Total other income (expense), net	(4,627)	(2,171)	(2,922)
Loss before income taxes	(25,777)	(37,701)	(31,244)
Provision for income taxes	61	85	70
Net loss	$ (25,838)	$ (37,786)	$ (31,314)
Net loss per share:
Basic and diluted (in USD per share)	$ (0.52)	$ (1.00)	$ (7.82)
Shares used in computing net loss per share:
Basic and diluted (in shares)	50,141	37,604	4,006
Other comprehensive income:
Change in unrealized gain/loss on short-term investments, net of tax	$ 0	$ 0	$ 0
Comprehensive loss	$ (25,838)	$ (37,786)	$ (31,314)

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Series D-2 Convertible Preferred Stock	Series A-2 Convertible Preferred Stock	Preferred Stock	Preferred Stock Series D-2 Convertible Preferred Stock	Preferred Stock Series A-2 Convertible Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Deficit
Beginning balance, shares at Dec. 31, 2012				106,947			3,504
Beginning balance at Dec. 31, 2012	$ (8,067)			$ 31,940			$ 4	$ 19,471	$ (59,482)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New issuances, shares					15,269
New issuances		$ 21,794			$ 21,794
Conversion of preferred stock to common stock upon IPO	0
Reclass of warrant liabilities to APIC upon IPO	0
Issuance of common stock upon exercise of stock options, shares							448
Issuance of common stock upon exercise of stock options	602							602
Issuance of restricted common stock							119
Vesting of early exercised stock options	0
Stock-based compensation	1,949							1,949
Net loss	(31,314)								(31,314)
Issuance of common stock and stock options to acquire Face It, Corp., shares							1,423
Issuance of common stock and stock options to acquire Face It, Corp.	12,068						$ 1	12,067
Ending balance at Dec. 31, 2013	(2,968)			$ 53,734			$ 5	34,089	(90,796)
Ending balance, shares at Dec. 31, 2013				122,216			5,494
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New issuances, shares						166	11,500
New issuances	70,626		$ 509			$ 509	$ 11	70,615
Conversion of preferred stock to common stock upon IPO, shares				(122,382)			30,595
Conversion of preferred stock to common stock upon IPO	(54,243)			$ (54,243)			$ 31	54,212
Reclass of warrant liabilities to APIC upon IPO	2,647							2,647
Issuance of common stock upon exercise of stock options and warrants, shares							1,556
Issuance of common stock upon exercise of stock options and warrants	1,112						$ 2	1,110
Issuance of common stock upon vesting of restricted stock units, shares							15
Issuance of common stock under ESPP, shares							156
Issuance of common stock under ESPP	660							660
Issuance of unregistered common stock							6
Vesting of early exercised stock options	200							200
Stock-based compensation	6,753							6,753
Net loss	(37,786)								(37,786)
Ending balance at Dec. 31, 2014	41,753			$ 0			$ 49	170,286	(128,582)
Ending balance, shares at Dec. 31, 2014				0			49,322
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of preferred stock to common stock upon IPO	0
Reclass of warrant liabilities to APIC upon IPO	0
Issuance of common stock upon exercise of stock options and warrants, shares							992
Issuance of common stock upon exercise of stock options and warrants	1,266						$ 1	1,265
Issuance of common stock upon vesting of restricted stock units, shares							566
Issuance of common stock upon vesting of restricted stock units	0						$ 1	(1)
Issuance of common stock under ESPP, shares							306
Issuance of common stock under ESPP	1,369							1,369
Vesting of early exercised stock options	0
Forfeiture of unvested restricted common stock, shares							(21)
Forfeiture of unvested restricted common stock	0
Stock-based compensation	7,730							7,730
Net loss	(25,838)								(25,838)
Ending balance at Dec. 31, 2015	$ 26,280			$ 0			$ 51	$ 180,649	$ (154,420)
Ending balance, shares at Dec. 31, 2015				0			51,165

Consolidated Statements of Stockholders' Equity (Deficit) Parenthetical - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Preferred Stock \| Series D-2 Convertible Preferred Stock
Stock Issuance Costs		$ 200
Common Stock
Stock Issuance Costs	$ 4,239

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
Consolidated Statements of Cash Flows $ in Thousands	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Cash flows from operating activities:
Net loss	$ (25,838)	$ (37,786)	$ (31,314)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	7,388	6,463	4,415
Provision for doubtful accounts	171	76	89
Stock-based compensation	7,730	6,753	1,949
Loss (gain) on disposal of property and equipment	10	1	(5)
Non-cash interest expense	350	293	6
Changes in fair value of convertible preferred and common stock warrant liabilities	0	(1,745)	1,871
Others	(36)	7	0
Changes in operating assets and liabilities:
Accounts receivable	(2,410)	(1,390)	(1,574)
Prepaid expenses and other current assets	(224)	(216)	(322)
Other assets	(312)	(128)	(136)
Accounts payable	(1,610)	300	196
Accrued and other current liabilities	426	1,863	1,429
Accrued federal fees and sales tax liability	441	440	2,325
Deferred revenue	1,038	1,012	106
Other liabilities	(135)	(208)	6
Net cash used in operating activities	(12,939)	(24,279)	(20,959)
Cash flows from investing activities:
Purchases of property and equipment	(1,116)	(1,025)	(554)
Cash paid to acquire Face It, Corp., net of cash acquired of $128	0	0	(2,836)
Decrease (increase) in restricted cash	806	(25)	(121)
Purchase of short-term investments	(20,000)	(49,992)	0
Proceeds from maturity of short-term investments	40,000	30,000	2,490
Net cash provided by (used in) investing activities	19,690	(21,042)	(1,021)
Cash flows from financing activities:
Net proceeds from IPO, net of payments for offering costs	0	71,459	0
Payments for deferred offering costs	0	0	(821)
Net proceeds from issuance of convertible preferred stock	0	0	21,794
Proceeds from exercise of common stock options and warrants	1,266	1,212	702
Proceeds from sale of common stock under ESPP	1,369	660	0
Proceeds from notes payable	0	19,536	5,000
Repayments of notes payable	(3,447)	(1,556)	(810)
Payments of capital leases	(5,744)	(5,449)	(4,598)
Proceeds from revolving line of credit	0	0	18,500
Repayments on revolving line of credit	0	0	(6,000)
Net cash provided by (used in) financing activities	(6,556)	85,862	33,767
Net increase in cash and cash equivalents	195	40,541	11,787
Cash and cash equivalents:
Beginning of period	58,289	17,748	5,961
End of period	58,484	58,289	17,748
Supplemental disclosures of cash flow data:
Cash paid for interest	4,340	3,869	1,088
Cash paid for income taxes	186	46	132
Non-cash investing and financing activities:
Equipment obtained under capital lease	6,284	5,886	4,747
Equipment purchased and unpaid at period-end	151	11	10
Deferred IPO costs incurred but unpaid at period-end	0	0	1,346
Reclass of deferred IPO costs to additional paid-in capital	0	2,179	0
Net cashless exercise of preferred stock warrants to Series A-2 convertible preferred stock	0	509	0
Vesting of early exercised stock options	0	200	0
Reclass of warrants liabilities to additional paid-in capital upon IPO	0	2,647	0
Conversion of convertible preferred stock to common stock upon IPO	0	54,243	0
Conversion of accrued federal fees to note payable, net	$ 1,675	$ 0	$ 4,075

Description of Business and Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Description of Business and Summary of Significant Accounting Policies

1. Description of Business and Summary of Significant Accounting Policies

Five9, Inc. and its wholly-owned subsidiaries (the “Company”) is a provider of cloud software for contact centers. The Company was incorporated in Delaware in 2001 and is headquartered in San Ramon, California. The Company has offices in Europe and Asia, which primarily provide research, development and client support services.

Basis of Presentation

The accompanying consolidated financial statements have been prepared in accordance with U.S. GAAP and applicable rules and regulations of the SEC regarding annual financial reporting. All intercompany transactions and balances have been eliminated in consolidation. As the Company is an emerging growth company, as defined in the Jumpstart Our Business Startups Act of 2012 (the “JOBS Act”), it can delay the adoption of new accounting standards until those standards would otherwise apply to privately-held companies. However, the Company has elected to comply with all new or revised accounting standards on the relevant dates on which adoption of such standards is required for non-emerging growth publicly-held companies. Under the JOBS Act, such election is irrevocable.

Use of Estimates

The preparation of consolidated financial statements in accordance with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenue and expenses during the reporting period. The significant estimates made by management affect revenue, the allowance for doubtful accounts, intangible assets, goodwill, loss contingencies, including the Company’s accrual for federal fees and sales tax liability, accrued liabilities, stock-based compensation, fair value calculations of the convertible preferred and common stock warrant liabilities, provision for income taxes and uncertain tax positions. Management periodically evaluates such estimates and they are adjusted prospectively based upon such periodic evaluation. Actual results could differ from those estimates.

Foreign Currency

The functional currency of the Company’s foreign subsidiaries is the U.S. dollar. For these subsidiaries, the monetary assets and liabilities are re-measured into U.S. dollars at the current exchange rate as of the balance sheet date, and all non-monetary assets and liabilities are re-measured into U.S. dollars at historical exchange rates. Revenues and expenses are converted using average rates in effect on a monthly basis. Exchange gains and losses resulting from foreign currency transactions were not significant in any period and are reported in “Other income (expense), net” in the consolidated statements of operations and comprehensive loss.

Cash and Cash Equivalents

The Company considers highly liquid instruments with a maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits cash and cash equivalents with financial institutions that management believes are of high credit quality. Cash equivalents consist of money market funds and certificates of deposit with original maturities of three months or less, and are stated at cost plus accrued interest, which approximates fair value.

Short-Term Investments

The Company considers all investments in marketable securities with original maturities at the date of purchase of more than three months to be short-term investments. Short-term investments are classified as available-for-sale at the time of purchase and the Company reevaluates such classification at each balance sheet date. Unrealized gains and losses for short-term investments are included in accumulated other comprehensive income (loss), a component of stockholders’ equity. Any unrealized losses that are considered to be other-than-temporary impairments are recorded in “Other income (expense), net” in the consolidated statements of operations and comprehensive loss. Realized gains (losses) on the sale of short-term investments are determined using the specific-identification method and recorded in “Other income, net” in the consolidated statements of operations and comprehensive loss. Interest and dividends are included in interest income when earned.

Concentration Risks

Financial instruments, which potentially subject the Company to significant concentrations of credit risk, consist primarily of cash and cash equivalents, short-term investments and accounts receivable. A significant portion of the Company’s cash and cash equivalents is held at one large reputable financial institution. Total cash and cash equivalents in excess of insured limits were $58.0 million as of December 31, 2015 and 2014. The Company has not experienced any losses in such accounts.

As of December 31, 2015 and 2014, no single client represented more than 10% of accounts receivable. For the years ended December 31, 2015, 2014 and 2013, no single client represented more than 10% of revenue.

Allowance for Doubtful Accounts

The Company records a provision for doubtful accounts based on historical experience and a detailed assessment of the collectability of its accounts receivable. In estimating the allowance for doubtful accounts, management considers, among other factors, the aging of the accounts receivable, historical write-offs and the creditworthiness of each client. If circumstances change, such as higher-than-expected defaults or an unexpected material adverse change in a major client’s ability to meet its financial obligations, the Company’s estimate of the recoverability of the amounts due could be reduced by a material amount.

The following table presents the changes in the allowance for doubtful accounts (in thousands):



	Year Ended December 31,
	2015			2014			2013
Balance, beginning of period	$	65		$	42		$	54
Add: bad debt expense	171			76			89
Less: write-offs, net of recoveries	(221		)	(53		)	(101		)
Balance, end of period	$	15		$	65		$	42

Property and Equipment, Net

Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows:



Asset Category		Estimated Useful Lives
Computer and network equipment		3 years
Computer software		3 years
Development costs		1 to 5 years
Furniture and fixtures		7 years
Leasehold improvements		Shorter of useful life or lease term

Maintenance and repairs are charged to expense as incurred, and improvements and betterments are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation and amortization are removed from the consolidated balance sheet and any resulting gain or loss is reflected in the consolidated statements of operations and comprehensive loss in the period realized.

The Company evaluates the recoverability of property and equipment for possible impairment whenever events or circumstances indicate that the carrying amount of such assets or asset groups may not be recoverable. Recoverability of these assets is measured by a comparison of the carrying amounts to the future undiscounted cash flows the assets or asset groups are expected to generate. If such evaluation indicates that the carrying amount of the assets or asset groups is not recoverable, the carrying amount of such assets or asset groups is reduced to fair value. No impairment losses have been recognized in any of the periods presented.

Business Combinations

When the Company acquires businesses, it allocates the purchase price to assets and liabilities, and identifiable intangible assets acquired at the acquisition date based upon their estimated fair values. The excess of the purchase consideration of an acquired business over the fair value of the underlying net tangible and intangible assets acquired and liabilities assumed is recorded as goodwill. This allocation and valuation require management to make significant estimates and assumptions, especially with respect to intangible assets, which can include, but are not limited to, the cash flows that an asset is expected to generate in the future, the appropriate weighted-average cost of capital, and the cost savings expected to be derived from acquiring an asset. These estimates are inherently uncertain and subject to refinement during a measurement period that may be up to one year from the acquisition date.

In addition, uncertain tax positions and tax-related valuation allowances assumed in connection with a business combination are initially estimated as of the acquisition date. The Company continues to evaluate these items and record any adjustments to the preliminary estimates to goodwill provided that the Company is within the measurement period. Subsequent to the measurement period, changes to these uncertain tax positions and tax related valuation allowances will affect the Company’s provision for income taxes in the consolidated statements of operations and comprehensive loss.

Goodwill and Intangible Assets

The Company records goodwill when the consideration paid in a business combination exceeds the fair value of the net tangible assets and the identified intangible assets acquired. Goodwill is not amortized, but instead is required to be tested for impairment annually and whenever events or changes in circumstances indicate that the carrying value of goodwill may exceed its fair value.

The Company performs testing for impairment of goodwill in its fourth quarter, or as events occur or circumstances change that would more likely than not reduce the fair value of the Company's single reporting unit below its carrying amount. A qualitative assessment is first made to determine whether it is necessary to perform the two-step quantitative goodwill impairment test. This initial qualitative assessment includes, among other things, consideration of: (i) market capitalization of the Company, (ii) past, current and projected future earnings and equity; (iii) recent trends and market conditions; and (iv) valuation metrics involving similar companies that are publicly-traded and acquisitions of similar companies, if available. If this initial qualitative assessment indicates that it is more likely than not that impairment exists, a second analysis will be performed, involving a comparison between the estimated fair values of the Company’s reporting unit with its respective carrying amount including goodwill. If the carrying value exceeds estimated fair value, there is an indication of potential impairment, and a third analysis is performed to measure the amount of impairment. The third analysis involves calculating an implied fair value of goodwill by measuring the excess of the estimated fair value of the reporting unit over the aggregate estimated fair values of the individual assets less liabilities. If the carrying value of goodwill exceeds the implied fair value of goodwill, an impairment charge is recorded for the excess.

Intangible assets, consisting of acquired developed technology, domain names, customer relationships and non-compete agreements, are carried at cost less accumulated amortization. All intangible assets have been determined to have definite lives and are amortized on a straight-line basis over their estimated remaining economic lives, ranging from three to seven years. Amortization expense related to developed technology is included in cost of revenue. Amortization expense related to customer relationships is included in sales and marketing expense. Amortization expense related to domain names and non-compete agreements is included in general and administrative expense. Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate an asset's carrying value may not be recoverable.

Revenue Recognition

The Company’s revenue consists of subscription services and related usage as well as professional services. The Company charges clients monthly subscription fees for access to the Company’s VCC solution. The monthly subscription fees are primarily based on the number of agent seats, as well as the specific VCC functionalities and applications deployed by the client. Agent seats are defined as the maximum number of named agents allowed to concurrently access the VCC cloud platform. Clients typically have more named agents than agent seats. Multiple named agents may use an agent seat, though not simultaneously. Substantially all of the Company’s clients purchase both subscriptions and related telephony usage. A small percentage of the Company's clients subscribe to its platform but purchase telephony usage directly from a wholesale telecommunications service provider. The Company does not sell telephony usage on a stand-alone basis to any client. The related usage fees are based on the volume of minutes used for inbound and outbound client interactions. The Company also offers bundled plans, generally for smaller deployments, whereby the client is charged a single monthly fixed fee per agent seat that includes both subscription and unlimited usage in the contiguous 48 states and, in some cases, Canada. Professional services revenue is derived primarily from VCC implementations, including application configuration, system integration, optimization, education and training services. Clients are not permitted to take possession of the Company’s software.

The Company offers monthly, annual and multiple-year contracts to its clients, generally with 30 days’ notice required for changes in the number of agent seats and sometimes with a minimum number of agent seats requirement. Larger clients typically choose annual contracts, which generally include an implementation and ramp period of several months. Fixed subscription fees (including bundled plans) are generally billed monthly in advance, while related usage fees are billed in arrears. Support activities include technical assistance for the Company’s solution and upgrades and enhancements to the VCC cloud platform on a when-and-if-available basis, which are not billed separately.

The Company generally requires advance deposits from its clients based on estimated usage when such usage is not billed as part of a bundled plan. Fees for certain clients’ usage are applied against the advance deposit resulting in continuous consumption and therefore requires frequent replenishment of the deposit. Any unused portion of the deposit is refundable to the client upon termination of the arrangement, provided all amounts due have been paid. All fees, except usage deposits, are non-refundable.

Professional services are primarily billed on a fixed-fee basis and are performed by the Company directly or, alternatively, clients may also choose to perform these services themselves or engage their own third-party service providers.

The Company’s sales arrangements generally involve multiple deliverables, including subscription services and related usage as well as professional services, all of which have stand-alone value to the client. The Company allocates arrangement consideration to these deliverables based on the relative stand-alone selling price method in accordance with the selling price hierarchy, which includes: (i) Vendor Specific Objective Evidence (“VSOE”) if available; (ii) Third-Party Evidence (“TPE”) if VSOE is not available; and (iii) Best Estimate of Selling Price (“BESP”) if neither VSOE nor TPE is available.

VSOE. The Company determines VSOE based on its historical pricing and discounting practices for the specific service when sold separately. In determining VSOE, the Company requires that a substantial majority of the selling prices for these services fall within a reasonably narrow pricing range. The Company limits its assessment of VSOE for each element to either the price charged when the same element is sold separately or the price established by management, having the relevant authority to do so, for an element not yet sold separately. The Company has not met the criteria to establish selling prices based on VSOE.

TPE. When VSOE cannot be established for deliverables in multiple element arrangements, the Company applies judgment with respect to whether it can establish a selling price based on TPE. TPE is determined based on competitor prices for similar deliverables when sold separately. The Company’s services are significantly differentiated such that the comparable pricing of deliverables with similar functionality cannot be obtained. Furthermore, the Company is unable to reliably determine the stand-alone selling prices of similar deliverables sold by competitors. As a result, the Company has not met the criteria to establish selling prices based on TPE.

BESP. Since the Company is unable to establish a selling price using VSOE or TPE, it uses BESP in its allocation of arrangement consideration. The objective of BESP is to determine the price at which the Company would transact a sale if the product or service were sold on a stand-alone basis. The Company determines BESP for deliverables by considering multiple factors including prices it charges for similar offerings, pricing policies, market conditions and the competitive landscape. The Company limits the amount of allocable arrangement consideration to amounts that are fixed or determinable and that are not contingent on future performance or future deliverables.

The Company recognizes revenue for each unit of accounting when all of the following criteria have been met:


•	persuasive evidence of an arrangement exists;


•	delivery has occurred;


•	the fee is fixed or determinable; and


•	collection is reasonably assured.

Revenue allocated to the separate accounting units is recognized as follows:


•	fixed subscription revenue is recognized on a straight-line basis over the applicable term, predominantly the monthly contractual billing period;


•	variable usage revenue is recognized as actual usage occurs. Usage revenue in subscription arrangements that include bundled usage is recognized on a straight-line basis over the applicable term, as the Company cannot reliably estimate client usage patterns; and


•	professional services revenue is recognized as services are performed using the proportional performance method, with performance measured based on labor hours, assuming all other revenue recognition criteria have been met.

At the time of each revenue transaction, the Company assesses whether fees under the arrangement are fixed or determinable and whether collection is reasonably assured. For arrangements where the fee is not fixed or determinable, the Company recognizes revenue as these amounts become due and payable. The Company assesses collection based on a number of factors, including past transaction history and the creditworthiness of the client. If the Company determines that collection of fees is not reasonably assured, it defers the revenue and recognizes revenue at such time when collection becomes reasonably assured, which is generally upon receipt of payment. The Company maintains a revenue reserve for potential credits to be issued in accordance with service level agreements or for other revenue adjustments.

The revenue recognition standards include guidance relating to any tax assessed by a governmental authority that is directly imposed on a revenue-producing transaction between a seller and a customer and may include, but is not limited to, sales, use, value added and excise taxes. The Company records USF contributions and other regulatory costs on a gross basis in its consolidated statements of operations and comprehensive loss and records surcharges and sales, use and excise taxes billed to its clients on a net basis. The cost of gross USF contributions payable to the USAC and suppliers is presented as a cost of revenue in the consolidated statements of operations and comprehensive loss. For the years ended December 31, 2015, 2014 and 2013, total USF contributions and other regulatory costs included in cost of revenue were $6.2 million, $4.4 million and $3.9 million, respectively. Surcharges and sales, use and excise taxes incurred in excess of amounts billed to the Company’s clients are presented in general and administrative expense in the consolidated statements of operations and comprehensive loss.

Deferred Revenue

Deferred revenue consists of billings or payments received from clients for subscription service, usage and professional services in advance of revenue recognition and are recognized as the revenue recognition criteria are met. The Company generally invoices its clients monthly in advance for subscription services. Accordingly, the deferred revenue balance does not represent the total contract value of sales arrangements. The current portion of deferred revenue represents the amount that is expected to be recognized as revenue within one year from the balance sheet date.

Cost of Revenue

Cost of revenue consists primarily of personnel costs (including stock-based compensation), fees that the Company pays to telecommunications providers for usage, USF contributions and other regulatory costs, depreciation and related expenses of the servers and equipment, costs to build out and maintain co-location data centers, and allocated office and facility costs and amortization of acquired technology. Personnel costs include those associated with support of the Company’s solution, clients and data center operations, as well as with providing professional services. Data center costs include costs to build out and setup, as well as co-location fees for the right to place the Company’s servers in data centers owned by third parties.

Research and Development

Research and development expenses consist primarily of salary and related expenses (including stock-based compensation) for personnel related to the development of improvements and expanded features for our services, as well as quality assurance, testing, product management and allocated overhead. Research and development costs are expensed as incurred except for internal use software development costs that qualify for capitalization. The Company reviews development costs incurred for internal-use software in the application development stage and assesses costs for capitalization. As of December 31, 2015 and 2014, the amount of capitalized internal-use software development costs was immaterial.

Advertising Costs

We primarily advertise our services through the web and in conjunction with partners. Advertising costs are expensed as incurred and were $9.2 million, $8.7 million and $7.3 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Commissions

Commissions consist of variable compensation earned by sales personnel and referral fees we paid to third parties. Sales commissions associated with the acquisition or renewal of a client contract are recognized as sales and marketing expense as incurred. Commission expense was $7.2 million, $6.4 million and $4.8 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Stock-Based Compensation

All stock-based compensation granted to employees and non-employee directors is measured as the grant date fair value of the award. The Company estimates the fair value of stock options and purchase rights under the Company's 2014 employee stock purchase plan (“ESPP”) using the Black-Scholes option-pricing model. The fair value of restricted stock awards is equal to the fair value of the Company’s common stock on the date of grant. Compensation expense is recognized net of estimated forfeitures using the straight-line method over the service period, which is generally the vesting period.

Convertible Preferred and Common Stock Warrant Liabilities

Prior to the Company's IPO, convertible preferred stock warrants and common stock warrants included provisions that potentially adjust the number of shares to be issued on settlement, or that potentially adjust the exercise prices, which made these instruments freestanding and accordingly they were classified as liabilities on the Company’s consolidated balance sheets. These warrant liabilities were subject to re-measurement at each balance sheet date until April 3, 2014 when, in connection with the Company's IPO, all the then-outstanding convertible preferred stock warrants became warrants to purchase common stock and the carrying value of the liabilities had been reclassified to additional paid-in capital.

Income Taxes

The Company accounts for income taxes using the asset and liability method. Deferred tax assets and liabilities are recognized for the estimated future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis. Deferred tax assets and liabilities are measured using enacted tax rates in effect for the year in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in operations in the period that includes the enactment date. The Company records a valuation allowance to reduce its deferred tax assets to the amount of future tax benefit that is more likely than not to be realized. As of December 31, 2015 and 2014, the Company recorded a full valuation allowance against the net deferred tax assets because of its history of operating losses in the United States. The Company classifies interest and penalties on unrecognized tax benefits as income tax expense.

Net Loss Per Share

Basic net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock outstanding during the period, and excludes any dilutive effects of employee stock-based awards and warrants. Diluted net income per share is computed giving effect to all potentially dilutive common shares, including common stock issuable upon exercise of stock options and warrants, vesting of restricted stock and purchases under the ESPP. In periods of net loss, all potentially issuable common shares are excluded from the diluted net loss per share computation because they are anti-dilutive. Therefore, basic and diluted net loss per share are the same for all years presented in the consolidated statements of operations and comprehensive loss.

The Company applied the two-class method to calculate basic and diluted net loss per share of common stock in periods in which shares of convertible preferred stock were outstanding, as shares of convertible preferred stock are participating securities due to their dividend rights. The two-class method is an earnings allocation method under which earnings per share is calculated for common stock considering a participating security’s rights to undistributed earnings as if all such earnings had been distributed during the period. The Company’s participating securities are not included in the computation of net loss per share in periods of net loss because the preferred shareholders have no contractual obligation to participate in losses.

Indemnification

Certain of the Company’s agreements with clients include provisions for indemnification against liabilities if its services infringe a third-party’s intellectual property rights. To date, the Company has not incurred any material costs as a result of such indemnification provisions and the Company has not accrued any liabilities related to such obligations in the consolidated financial statements as of December 31, 2015 or 2014.

Segment Information

The Company has determined that its Chief Executive Officer is its chief operating decision maker. The Company’s Chief Executive Officer reviews financial information presented on a consolidated basis for purposes of assessing performance and making decisions on how to allocate resources. Accordingly, the Company has determined that it operates in a single reportable segment.

Recently Adopted Accounting Pronouncement

In November 2015, the FASB issued ASU No. 2015-17, Balance Sheet Classification of Deferred Taxes. This ASU eliminates the requirement for companies to present deferred tax assets and liabilities as current and noncurrent on the balance sheet and, instead, requires companies to classify all deferred tax assets and liabilities as noncurrent. As permitted by ASU 2015-17, the Company early-adopted this new guidance at the beginning of the fourth quarter of 2015 and applied it prospectively. No prior periods were retrospectively adjusted.

Recent Accounting Pronouncement Not Yet Effective

In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606), which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The ASU will replace most existing revenue recognition guidance in U.S. GAAP when it becomes effective. The ASU No. 2014-09 is originally effective for the Company's annual and interim reporting periods beginning January 1, 2017. The standard permits the use of either the retrospective or cumulative effect transition method. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, which defers the effective date of ASU 2014-09 for all entities by one year while providing an option to early adopt the standard on the original effective date. Accordingly, the new revenue standard is effective for the Company's annual and interim reporting periods beginning January 1, 2018. The Company has not yet selected a transition method or determined the effect of the standard on its ongoing financial reporting.

Acquisition of Face It, Corp.

12 Months Ended

Dec. 31, 2015

Business Combinations [Abstract]

Acquisition of Face It, Corp.

2. Acquisition of Face It, Corp.

On October 18, 2013 (the “Acquisition Date”), the Company completed its acquisition of Face It, Corp., which the Company refers to as SoCoCare, a social engagement and mobile client care solution provider, pursuant to an Agreement and Plan of Merger (the “Agreement”). In accordance with the terms and subject to the conditions set forth in the Agreement, the Company acquired all of the outstanding equity securities of Face It, Corp. The acquisition was accounted for as a business combination in accordance with the FASB Accounting Standards Codifications (“ASC”) Topic 805, “Business Combinations”. The Company has integrated SoCoCare and its technology to add social engagement and mobile client care applications to its solution.

The Company acquired SoCoCare for a total purchase price of $15.0 million. The purchase price consisted of $3.0 million of cash, approximately 1,423,000 shares of common stock valued at $12.1 million, and 22,000 stock options with a total fair value of $0.1 million, of which $4 thousand was allocated to the purchase price and $0.1 million was allocated to post-combination stock-based compensation.

The total purchase price was allocated to the net assets acquired based upon their fair values as of the Acquisition Date as set forth below. The excess of the purchase price over the net assets acquired was recorded as goodwill. The goodwill represents SoCoCare’s assembled workforce, its know-how and the business development initiatives that allow SoCoCare to acquire new customers, create new technologies and generate revenue. Goodwill is not deductible for U.S. tax purposes.

The following table summarizes the fair values of the assets acquired and liabilities assumed at the Acquisition Date (in thousands):



	As of October 18, 2013
Tangible assets acquired	$	177
Intangible assets:
Developed technology	2,460
Customer relationships	520
Domain names	50
Non-compete agreements	140
Goodwill	11,798
Current liabilities	(113		)
Total purchase price	$	15,032

Upon the acquisition, the Company hired or contracted certain of SoCoCare’s employees, including its three founders (the “Founders”). In connection with the employment and service agreements, the Company issued 118,577 unvested shares of restricted common stock to the Founders that were contingent upon continuing employment or services and therefore excluded from the purchase price of the acquisition (Note 8).

The fair values of the acquired intangible assets were determined using Level 3 inputs which are not observable in the market (Note 3). Details related to estimated useful lives and the valuation techniques utilized for estimating fair value of the intangible assets acquired are shown below:



Intangible Type	Valuation Technique	Useful Life
Developed technology	Excess earnings method	7 years
Customer relationships	Cost approach	5 years
Domain names	Relief from royalty method	5 years
Non-compete agreements	Modified discounted cash flow	3 years

The assets, liabilities and operating results of SoCoCare have been reflected in the consolidated financial statements from the Acquisition Date and approximately $42 thousand of revenue and $0.8 million of expenses related to the operations of SoCoCare have been included in the accompanying consolidated statement of operations and comprehensive loss for the year ended December 31, 2013. The Company expensed $0.6 million of acquisition-related costs as general and administrative expenses in the consolidated statements of operations and comprehensive loss during the year ended December 31, 2013. For 2015 and 2014, it is impracticable to determine the results of operations or the revenue from the SoCoCare acquisition as the acquired business was integrated into the Company's operations in 2014 and is not separately identifiable.

The following pro forma condensed financial information presents the results of operations of the Company and SoCoCare as if the acquisition had occurred on January 1, 2012 (unaudited and in thousands).



	2013
Revenue	$	84,260
Net loss	$	(32,787	)

The pro forma financial information is provided for comparative purposes only and is not necessarily indicative of what the actual results would have been had the acquisition occurred at the beginning of year 2012. Pro forma net loss includes adjustments related to amortization expense in connection with intangible assets, interest expense on debt, stock-based compensation expense and acquisition-related costs.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1497-128463

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1490-128463

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
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-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7008-128479

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1486-128463

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4845-128472

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1500-128463

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1524-128463

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e7000-128479

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
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-URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4934-128472

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4926-128472

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1383-128463

Reference 15: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6996-128479

+ Details

Fair Value Measurements

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

3. Fair Value Measurements

The Company carries cash equivalents and short-term investments consisting of money market funds and marketable securities at fair value on a recurring basis. Fair value is based on the price that would be received from selling an asset in an orderly transaction between market participants at the measurement date. Fair value is estimated by applying the following hierarchy, which prioritizes the inputs used to measure fair value into three levels and bases the categorization within the hierarchy upon the lowest level of input that is available and significant to the fair value measurement:

Level 1 — Observable inputs which include unadjusted quoted prices in active markets for identical assets.

Level 2 — Observable inputs other than Level 1 inputs, such as quoted prices for similar assets, quoted prices for identical or similar assets in inactive markets, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset.

Level 3 — Unobservable inputs that are supported by little or no market activity and that are based on management’s assumptions, including fair value measurements determined by using pricing models, discounted cash flow methodologies or similar techniques.

The fair value of assets and liabilities carried at fair value was determined using the following inputs (in thousands):



	December 31, 2015
	Total		Level 1
Assets
Cash equivalents:
Money market funds	$	20,010	$	20,010

	December 31, 2014
	Total		Level 1
Assets
Short-term investments:
U.S. Treasury bills	$	20,000	$	20,000

The Company’s other financial instruments' fair value, including accounts receivable, accounts payable and other current liabilities, approximate its carrying value due to the relatively short maturity of those instruments. The carrying amounts of the Company's debt and capital leases approximate their fair value, which is the present value of expected future cash payments based on assumptions about current interest rates and the creditworthiness of the Company. The inputs used to measure fair value of the Company's debt and capital leases are classified as Level 2 inputs.

The Company acquired intangible assets of $3.2 million in connection with its acquisition of SoCoCare in October 2013. The fair value of the intangible assets acquired was determined using Level 3 inputs. Key assumptions include the level and timing of expected future cash flows, and discount rates consistent with the level of risk and the economy in general.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Cash, Cash Equivalents and Short-Term Investments

12 Months Ended

Dec. 31, 2015

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Cash, Cash Equivalents and Short-Term Investments

4. Cash, Cash Equivalents and Short-Term Investments

Cash and cash equivalents consisted of the following (in thousands):



	December 31,
	2015		2014
Cash and cash equivalents:
Cash	$	38,474	$	58,289
Money market funds	20,010		—
Total cash and cash equivalents	$	58,484	$	58,289

As of December 31, 2015, the Company was required to maintain $7.5 million in deposits in connection with its credit agreement with a lender as a compensating balance (see Note 7).

As of December 31, 2014, short-term investments consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Aggregate Fair Value
U.S. Treasury bills	$	20,000	$	—	$	—	$	20,000

Restricted Cash

As of December 31, 2015, the Company's restricted cash balance was not material. As of December 31, 2014, the Company had restricted cash of $0.8 million that included $0.7 million related to a letter of credit issued to the Company’s landlord with respect to its lease obligation and $0.1 million under letters of credit primarily related to an insurance policy. These letters of credit were released during the first half of 2015. Restricted cash is included in 'Other assets' on the accompanying consolidated balance sheets.

Financial Statement Components

12 Months Ended

Dec. 31, 2015

Financial Statement Components [Abstract]

Financial Statement Components

5. Financial Statement Components

Accounts receivable, net consisted of the following (in thousands):



	December 31,
	2015			2014
Trade accounts receivable	$	9,554		$	7,482
Unbilled trade accounts receivable, net of advance client deposits	1,028			918
Allowance for doubtful accounts	(15		)	(65		)
Accounts receivable, net	$	10,567		$	8,335

Property and equipment, net consisted of the following (in thousands):



	December 31,
	2015			2014
Computer and network equipment	$	30,277		$	24,292
Computer software	3,566			2,264
Internal-use software development costs	128			—
Furniture and fixtures	1,113			1,030
Leasehold improvements	619			611
Property and equipment	35,703			28,197
Accumulated depreciation and amortization	(22,478		)	(15,626		)
Property and equipment, net	$	13,225		$	12,571

Depreciation and amortization expense associated with property and equipment was $6.9 million, $6.0 million, and $4.3 million for the years ended December 31, 2015, 2014 and 2013, respectively.

Property and equipment capitalized under capital lease obligations consist primarily of computer and network equipment and were as follows (in thousands):



	December 31,
	2015			2014
Gross	$	27,302		$	21,025
Less: accumulated depreciation and amortization	(16,429		)	(10,609		)
Total	$	10,873		$	10,416

Accrued and other current liabilities consisted of the following (in thousands):



	December 31,
	2015		2014
Accrued expenses	$	2,193	$	2,240
Accrued compensation and benefits	5,718		5,078
Accrued and other current liabilities	$	7,911	$	7,318

Goodwill and Intangible Assets

12 Months Ended

Dec. 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

6. Goodwill and Intangible Assets

Goodwill

Goodwill was recorded as a result of the Company's acquisition of SoCoCare in October 2013 (see Note 2).

During the fourth quarter of 2015, the Company completed its annual goodwill impairment test. Based on its assessment of the qualitative factors, management concluded that the fair value of the Company was more likely than not greater than its carrying amount as of December 31, 2015. As such, it was not necessary to perform the two-step quantitative goodwill impairment test. Subsequent to the 2015 annual impairment test, we believe there have been no significant events or circumstances negatively affecting the valuation of goodwill. As of December 31, 2015 and 2014, there was no impairment to the carrying value of the Company's goodwill.

Intangible Assets

Intangible assets were acquired in connection with the Company’s acquisition of SoCoCare in October 2013 (see Note 2). The components of intangible assets are as follows (in thousands):



	December 31, 2015							December 31, 2014
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Developed technology	$	2,460	$	(775	)	$	1,685	$	2,460	$	(423	)	$	2,037
Customer relationships	520		(229		)	291		520		(125		)	395
Domain names	50		(22		)	28		50		(12		)	38
Non-compete agreements	140		(103		)	37		140		(57		)	83
Total	$	3,170	$	(1,129	)	$	2,041	$	3,170	$	(617	)	$	2,553

Amortization expense related to intangible assets was $0.5 million, $0.5 million and $0.1 million for the years ended December 31, 2015, 2014 and 2013, respectively. As of December 31, 2015, the expected future amortization expense for intangible assets was as follows (in thousands):



Period	Expected Future Amortization Expense
2016	$	503
2017	465
2018	442
2019	351
2020	280
Total	$	2,041

Intangible assets are reviewed for impairment whenever events or changes in circumstances indicate an asset's carrying value may not be recoverable. The Company concluded that there was no impairment to the carrying value of its intangible assets as of December 31, 2015 and 2014.

- Definition

The entire disclosure for the aggregate amount of goodwill and a description of intangible assets, which may include (a) for amortizable intangible assets (also referred to as finite-lived intangible assets), the carrying amount, the amount of any significant residual value, and the weighted-average amortization period, (b) for intangible assets not subject to amortization (also referred to as indefinite-lived intangible assets), the carrying amount, and (c) the amount of research and development assets acquired and written off in the period, including the line item in the income statement in which the amounts written off are aggregated, if not readily apparent from the income statement. Also discloses (a) for amortizable intangibles assets in total and by major class, the gross carrying amount and accumulated amortization, the total amortization expense for the period, and the estimated aggregate amortization expense for each of the five succeeding fiscal years, (b) for intangible assets not subject to amortization the carrying amount in total and by major class, and (c) for goodwill, in total and for each reportable segment, the changes in the carrying amount of goodwill during the period (including the aggregate amount of goodwill acquired, the aggregate amount of impairment losses recognized, and the amount of goodwill included in the gain (loss) on disposal of a reporting unit). If any part of goodwill has not been allocated to a reportable segment, discloses the unallocated amount and the reasons for not allocating. For each impairment loss recognized related to an intangible asset (excluding goodwill), discloses: (a) a description of the impaired intangible asset and the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method for determining fair value, (c) the caption in the income statement or the statement of activities in which the impairment loss is aggregated, and (d) the segment in which the impaired intangible asset is reported. For each goodwill impairment loss recognized, discloses: (a) a description of the facts and circumstances leading to the impairment, (b) the amount of the impairment loss and the method of determining the fair value of the associated reporting unit, and (c) if a recognized impairment loss is an estimate not finalized and the reasons why the estimate is not final. May also disclose the nature and amount of any significant adjustments made to a previous estimate of an impairment loss.

+ References + Details

Debt

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Debt

7. Debt

2013 Loan and Security Agreement

The Company has a revolving line of credit of up to $20.0 million (“Revolving Credit Facility”) under a loan and security agreement with a lender, which was entered into in March 2013 and last amended in December 2014 (“2013 Loan and Security Agreement”). The Revolving Credit Facility carries a variable annual interest rate of the prime rate plus 0.50% and matures on December 1, 2016.

The 2013 Loan and Security Agreement is collateralized by substantially all the assets of the Company. The balance outstanding cannot exceed the lesser of (i) $20.0 million or (ii) an amount equal to the Company’s monthly recurring revenue for the three months prior multiplied by the average Dollar-Based Retention Rate over the prior twelve months, less the amount accrued for the Company’s Universal Service Fund (“USF”) obligation (accrued federal fees). As of December 31, 2015, the outstanding principal balance under the Revolving Credit Facility was $12.5 million, which has been disclosed as a current liability, and the amount available for additional borrowings was $7.5 million.

In connection with its acquisition of SoCoCare, the Company also borrowed $5.0 million under a term loan (the “Term Loan”) under the 2013 Loan and Security Agreement in October 2013. Monthly interest-only payments were due on the advance at the prime rate plus 1.50% through September 2014. Principal and interest payments are due in equal monthly installments from October 2014 through the maturity of the Term Loan in March 2017. As of December 31, 2015 and 2014, approximately $2.5 million and $4.5 million, respectively, in principal amount of this Term Loan was outstanding and is included as notes payable in the consolidated balance sheets.

The 2013 Loan and Security Agreement contains certain covenants, including the requirement that the Company maintain $7.5 million of cash deposited with the lender for the term of the 2013 Loan and Security Agreement. The Company was in compliance with these covenants as of December 31, 2015. The 2013 Loan and Security Agreement remains senior to other debts, including the debt issued under the 2014 Loan and Security Agreement discussed below.

2014 Loan and Security Agreement

The Company had a term loan facility of $30.0 million with a syndicate of two lenders (“Lenders”), which was entered into in February 2014 and amended in December 2014 and February 2015 (the “2014 Loan and Security Agreement”). The term loan facility was available to the Company in tranches. The first tranche for $20.0 million was advanced upon the closing of the agreement. The remaining $10.0 million was available for drawdown by the Company until February 20, 2016 in $1.0 million increments, which has now expired. The Company incurred $0.4 million in debt issuance costs in connection with borrowing the first tranche in February 2014. The term loan bears interest at a variable per annum rate equal to the greater of 10% or LIBOR plus 9%. Interest is due and payable on the last business day of each month during the term of the loan commencing in February 2014. Monthly principal payments are due beginning in February 2016 based on 1/60th of the outstanding balance at that time and will continue until all remaining principal outstanding under the term loan becomes due and payable in February 2019. As of December 31, 2015 and 2014, $20.0 million of this loan facility was outstanding and is included as notes payable in the consolidated balance sheets.

The term loan is secured by substantially all the assets of the Company and is subordinate to the 2013 Loan and Security Agreement. The 2014 Loan and Security Agreement contains certain covenants and includes the occurrence of a material adverse event, as defined in the agreement and determined by the Lenders, as an event of default. As of December 31, 2015, the Company was in compliance with these covenants.

In connection with entering into the 2014 Loan and Security Agreement, the Company issued to the Lenders warrants to purchase 177,865 shares of common stock at $10.12 per share, which vest and become exercisable over a ten year term from the date of issuance, based on amounts drawn under the $30.0 million term loan facility. Based on the drawdown of $20.0 million in February 2014, 118,577 shares of common stock issuable under the warrants vested and are exercisable by the Lenders. As of December 31, 2015, 59,288 shares of common stock issuable under the warrants pertaining to the undrawn $10.0 million were unvested, which were subsequently canceled on February 20, 2016 when the $10.0 million became unavailable for borrowing.

Promissory Note

In July 2013, the Company issued a promissory note to the USAC for $4.1 million in principal amount as a financing arrangement for that amount of accrued federal fees. The promissory note carries a fixed annual interest rate of 12.75% and is repayable in 42 equal monthly installments of principal and interest beginning in August 2013. As of December 31, 2015 and 2014, approximately $1.5 million and $2.6 million in principal amount, respectively, of this promissory note was outstanding and is included as notes payable in the accompanying consolidated balance sheets.

FCC Civil Penalty

In June 2015, the Company entered into a consent decree with the FCC Enforcement Bureau (Note 11), in which the Company agreed to pay a civil penalty of $2.0 million to the U.S. Treasury in twelve equal quarterly installments starting in July 2015 without interest. As a result, the Company discounted the $2.0 million liability, which was accrued in the third quarter of 2014 for the then tentative civil penalty, to its present value of $1.7 million at an annual interest rate of 12.75% to reflect the imputed interest and reclassified this discounted liability from 'Accrued federal fees' to 'Notes payable.' The $0.3 million discount was recorded as a reduction to general and administrative expense in the three months ended June 30, 2015 and is being recognized as interest expense over the payment term of the civil penalty. As of December 31, 2015, the outstanding civil penalty payable was $1.7 million, of which the net carrying value was $1.4 million and is included as 'Notes payable' in the accompanying condensed consolidated balance sheets.

As of December 31, 2015 and 2014, the Company’s outstanding debt is summarized as follows (in thousands):



	December 31,
	2015			2014
Term loan under 2014 Loan and Security Agreement	$	20,000		$	20,000
Term loan under 2013 Loan and Security Agreement	2,500			4,500
Promissory note to USAC	1,459			2,640
FCC civil penalty	1,667			—
Total notes payable, gross	25,626			27,140
Less: discount	(1,087		)	(1,216		)
Total notes payable, net carrying value	24,539			25,924
Revolving line of credit	12,500			12,500
Total debt, net carrying value	$	37,039		$	38,424
Less: current portion of debt *	(19,712		)	(3,146		)
Total debt, less current portion **	17,327			35,278


* Included in ‘Revolving line of credit’ and ‘Notes payable’ in the consolidated balance sheets.
** Included in ‘Notes payable - less current portion’ and ‘Revolving line of credit - less current portion’ in the consolidated balance sheets.

Maturities of the Company’s outstanding debt as of December 31, 2015 are as follows (in thousands):



Period	Amount to Mature
2016	$	20,173
2017	5,286
2018	4,334
2019	8,333
Total	$	38,126

Stockholders' Equity

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Stockholders' Equity

8. Stockholders’ Equity

Initial Public Offering

On April 9, 2014, the Company consummated its IPO and issued and sold 10,000,000 shares of common stock at a public offering price of $7.00 per share, less the underwriters’ discount. In addition, on April 22, 2014, the Company consummated the sale of an additional 1,500,000 shares of common stock to the underwriters of the Company's IPO pursuant to the underwriters’ exercise in full of their option to purchase 1,500,000 shares of common stock from the Company at the IPO price of $7.00 per share, less the underwriters' discount. The Company received aggregate proceeds of $74.9 million from the IPO after deducting underwriters’ discounts and commissions of $5.6 million, but before deducting offering expenses of approximately $4.2 million, of which $0.8 million had been paid prior to 2014 and the remaining $3.4 million had been paid in the first two quarters of 2014.

On April 3, 2014, a reverse stock split of the Company's then-outstanding common stock at a ratio of 4:1 was effected in connection with the IPO. Prior to such reverse stock split being effected, all outstanding convertible preferred stock elected to convert to common stock on a 1:1 basis.

Capital Structure

Convertible Preferred Stock

Prior to the IPO, the Company had outstanding 75,643,683 shares of Series A-2 convertible preferred stock, 18,565,794 shares of Series B-2 convertible preferred stock, 12,903,226 shares of Series C-2 convertible preferred stock, and 15,269,294 shares of Series D-2 convertible preferred stock.

On April 3, 2014, immediately prior to the effectiveness of the Company’s registration statement filed with the SEC and the reverse stock split being effected, all shares of the Company's outstanding convertible preferred stock converted into common stock on a 1:1 basis. These shares of common stock issued upon conversion of the convertible preferred stock represented 30,595,477 shares of common stock after giving effect to the 4:1 reverse stock split on April 3, 2014.

Common Stock

Pursuant to the Company's amended and restated certificate of incorporation (“Amended and Restated Certificate of Incorporation”), which became effective on April 8, 2014 in connection with the Company's IPO, the Company is authorized to issue 450,000,000 shares of common stock with a par value of $0.001 per share. As of December 31, 2015, the Company had 51,164,621 shares of common stock issued and outstanding.

Holders of the Company's common stock are entitled to dividends, if and when declared by the board of directors. In the event of liquidation, dissolution or winding up, subject to the rights of the holders of any then outstanding shares of preferred stock, holders of common stock will be entitled to receive the assets and funds of the Company that are legally available for distribution.

Preferred Stock

Pursuant to the Amended and Restated Certificate of Incorporation, the Company's board of directors is also authorized to designate and issue up to 5,000,000 shares of preferred stock with a par value of $0.001 per share in one or more series without stockholder approval and to fix the rights, preferences, privileges and restrictions thereof. As of December 31, 2015, there were no shares of preferred stock issued and outstanding.

Common Stock Subject to Forfeiture

Pursuant to employment and service agreements entered into in connection with the Company’s acquisition of SoCoCare in October 2013 (“Acquisition Date”), the Company issued 118,577 shares of unvested restricted common stock, the vesting of which was contingent upon continuing employment or services and subject to forfeiture. These shares were valued at $8.48 per share based on the Acquisition Date fair value of the Company’s common stock. This amount was recorded as stock-based compensation on a straight-line basis over the requisite service periods. During October 2014, 50% of such shares vested. As of December 31, 2014, there were 59,289 shares of such restricted common stock subject to forfeiture, which were included in issued and outstanding shares of common stock. During 2015, in accordance with the applicable stock issuance agreement, the vesting on 37,905 shares accelerated in connection with the termination of employment of a shareholder and the remaining 21,384 unvested shares were forfeited as a result of terminations of employment of the remaining employee-shareholders. As of December 31, 2015, there was no restricted common stock outstanding.

For the year ended December 31, 2015, stock-based compensation expense related to these shares was immaterial. For the years ended December 31, 2014 and 2013, $0.7 million and $0.2 million, respectively, was included as stock-based compensation expense related to these shares.

Warrants

As of December 31, 2015, the Company had outstanding warrants to purchase shares of common stock as follows (in thousands, except per share data):



Expiration Date	Exercise Price		Warrants Outstanding at December 31, 2015
October 2023	$	5.76	13
February 2024	$	10.12	178
Total			191

The table below is a summary of the Company’s common stock warrant activity during the year ended December 31, 2015 (in thousands, except per share data).



	Shares			Weighted Average Exercise Price
Outstanding as of December 31, 2014	360			$	5.59
Issued	—			—
Exercised	(169	)	(1)	0.65
Outstanding as of December 31, 2015	191			$	9.96

(1) In November 2015, warrants to purchase 168,711 shares of common stock were fully exercised at an exercise price of $0.65 per share pursuant to the cashless exercise method. Upon such exercises, the Company issued 151,905 shares of common stock.

Fair Value of Warrants

Prior to the IPO, the Company had outstanding warrants to purchase shares of its convertible preferred stock and common stock that were classified as liabilities. These warrants were subject to re-measurement at each balance sheet date, and any change in fair value was recognized as a component of other expense, net.

The Company estimated the fair value of each liability-classified warrant using the Black-Scholes option-pricing model and using the assumptions noted in the table below. Expected volatility is based upon the historical and implied volatility of a peer group of publicly traded companies. The expected term of warrants represents the contractual term of the warrants. The risk-free rate for the expected term of the warrants is based on the U.S. Treasury Constant Maturity at the time of issuance.



	IPO Date April 3, 2014			December 31, 2013
Fair value of Series A-2 preferred stock	$	1.75	(1)	$	2.69	(2)
Fair value of Series D-2 preferred stock	$	1.75	(1)	$	2.81	(2)
Fair value of common stock	$	7.00	(1)	*
Risk-free interest rate	0.13% to 2.73%			0.33% to 2.60%
Expected life	Remaining contractual life			Remaining contractual life
Expected dividends	—			—
Volatility	40% - 50%			45 %


(1) Fair value of the underlying stock is based on the Company's IPO price of $7.00 per share calculated on a pre-reverse split basis for preferred stock and post-reverse split basis for common stock.
(2) The per share data is on a pre-reverse split basis for preferred stock.
* There were no liability-classified common stock warrants at December 31, 2013.

Upon the conversion of the convertible preferred stock to common stock and the effectiveness of the reverse stock split of the Company's common stock, the outstanding convertible preferred stock warrants became warrants to purchase common stock and, upon the IPO, the Company’s outstanding common stock warrant liabilities became indexed to the Company's common stock and accordingly have been reclassified to additional paid-in capital.

Common Stock Reserved for Future Issuance

As of December 31, 2015, shares of common stock reserved for future issuance related to outstanding equity awards, warrants, and employee equity incentive plans were as follows (in thousands):



		December 31, 2015
Stock options outstanding		6,092
Restricted stock units outstanding		1,818
Shares available for future grant under 2014 Plan		5,079
Shares available for future issuance under ESPP		911
Common stock warrants outstanding		191
Total shares of common stock reserved		14,091

Equity Incentive Plans

Prior to the IPO, the Company granted stock options under its Amended and Restated 2004 Equity Incentive Plan, as amended (the “2004 Plan”). Under the terms of the 2004 Plan, the Company had the ability to grant incentive and nonstatutory stock options. Incentive stock options could only be granted to Company employees. Nonstatutory stock options could be granted to Company employees, directors and consultants. Such options are exercisable at prices, as determined by the board of directors, generally equal to the fair value of the Company’s common stock at the date of grant. Options granted to employees generally vest over a four-year period, with an initial vesting period of 12 months for 25% of the shares, and the remaining 75% of the shares vesting monthly on a ratable basis over the remaining 36 months. Options generally expire ten years after the grant date and are generally exercisable upon vesting. Vested options generally expire 90 days after termination of the optionee’s employment or relationship as a consultant or director, unless otherwise extended by the terms of the stock option agreement.

In March 2014, the Company’s board of directors and stockholders approved the 2014 Equity Incentive Plan (“2014 Plan”) and 5,300,000 shares of common stock were authorized for issuance under the 2014 Plan. In addition, on the first day of each year beginning in 2015 and ending in 2024, the 2014 Plan provides for an annual automatic increase to the shares reserved for issuance in an amount equal to 5% of the total number of shares outstanding on December 31st of the preceding calendar year or a lesser number as determined by the Company’s board of directors. Pursuant to the automatic annual increase, 2,558,231 and 2,466,124 additional shares were reserved under the 2014 Plan on January 1, 2016 and 2015. As of December 31, 2015, 5,079,164 shares of common stock were available for future grant under the 2014 Plan.

Upon the effectiveness of the 2014 Plan on April 3, 2014, no grants were made under the 2004 Plan. All shares reserved under the 2004 Plan became available for grant under the 2014 Plan. After the IPO, any forfeited or expired shares that would have otherwise returned to the 2004 Plan instead return to the 2014 Plan.

The 2014 Plan allows the Company to grant stock options, restricted stock units (“RSU”), restricted stock awards, performance stock awards, stock appreciation rights, performance cash awards, and other stock awards. To date, the Company has granted stock options and RSUs under the 2014 Plan. Stock options granted under the 2014 Plan are in general at a price equal to the fair market value of the common stock on the date of grant and vest over four years. The Company's stock options expire ten years from the date of grant. Each RSU granted under the 2014 Plan represents a right to receive one share of the Company’s common stock when the RSU vests. RSUs generally vest over one to four years.

Stock Options

A summary of the Company’s stock option activity during the year ended December 31, 2015 is as follows (in thousands, except years and per share data):



	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (1)
Outstanding as of December 31, 2014	7,164		$	4.34
Options granted	244		4.99
Options exercised	(840	)	1.51
Options forfeited or expired	(476	)	6.67
Outstanding as of December 31, 2015	6,092		$	4.58	6.4	$	27,243
Vested and expected to vest as of December 31, 2015	5,998		4.54		6.4	27,011
Exercisable as of December 31, 2015	4,057		3.55		5.5	22,004


(1) The aggregate intrinsic value amounts are computed based on the difference between the exercise price of the stock options and the fair market value of the Company’s common stock of $8.70 per share as of December 31, 2015 for all in-the-money stock options outstanding.

Following is additional information pertaining to the Company’s stock option activities (in thousands):



	Year Ended December 31,
	2015		2014		2013
Weighted-average grant date fair value per share of options granted	$	2.38	$	3.42	$	4.19
Grant-date fair value of options vested	4,824		3,847		1,417
Intrinsic value of options exercised ⁽¹⁾	3,233		9,808		2,145
Proceeds received from options exercised	1,268		1,127		702


(1) Intrinsic value of options exercised is the difference between the fair market value of the Company’s common stock at the time of exercise and the exercise price paid.

Restricted Stock Units

The Company commenced granting RSUs to employees upon the effectiveness of the 2014 Plan on April 3, 2014. A summary of RSU activity during the year ended December 31, 2015 is as follows (in thousands, except years and per share data):



	Number of Shares		Weighted Average Grant Date Fair Value Per Share
Outstanding as of December 31, 2014	1,370		$	5.21
RSUs granted	1,202		5.10
RSUs vested and released	(566	)	5.73
RSUs forfeited	(188	)	4.94
Outstanding as of December 31, 2015	1,818		$	5.01

Employee Stock Purchase Plan

In March 2014, the Company’s board of directors and stockholders adopted the 2014 Employee Stock Purchase Plan, or ESPP, and the shares authorized for issuance thereunder. The ESPP became effective on April 3, 2014.

The ESPP permits eligible employees to purchase shares of the Company’s common stock through payroll deductions with up to 15% of their pre-tax earnings subject to certain Internal Revenue Code limitations. The purchase price of the shares is 85% of the lower of the fair market value of the Company’s common stock on the first day of an offering period, except for the initial offering period, or the relevant purchase date. In addition, no participant may purchase more than 1,500 shares of common stock in each purchase period.

The number of shares of common stock originally reserved for issuance under the ESPP was 880,000 shares, which increases automatically each year, beginning on January 1, 2015 and continuing through January 1, 2024, by the lesser of (i) 1% of the total number of shares of our common stock outstanding on December 31 of the preceding calendar year; (ii) 1,000,000 shares of common stock (subject to adjustment to reflect any split or combination of our common stock); or (iii) such lesser number as determined by the Company’s board of directors. As of December 31, 2015, 911,106 shares of common stock were available for future issuance under the ESPP Plan. Pursuant to the automatic annual increase, 511,646 and 493,224 additional shares were reserved under the ESPP on January 1, 2016 and 2015.

During the year ended December 31, 2015, 305,987 shares were purchased by employees under the ESPP at a weighted-average price of $4.47 per share.

Stock-Based Compensation

Stock-based compensation expenses for the years ended December 31, 2015, 2014 and 2013 were as follows (in thousands):



	Year Ended December 31,
	2015		2014		2013
Cost of revenue	$	866	$	542	$	194
Research and development	1,790		1,931		499
Sales and marketing	1,800		1,510		751
General and administrative	3,274		2,770		505
Total stock-based compensation	$	7,730	$	6,753	$	1,949

As of December 31, 2015, unrecognized stock-based compensation expense by award type, net of estimated forfeitures, and their expected weighted-average recognition periods are summarized in the following table (in thousands, except years).



	Stock Option		RSU		ESPP
Unrecognized stock-based compensation expense	$	6,983	$	7,280	$	202
Weighted-average amortization period	2.1 years		3.0 years		0.4 years

The Company recognizes stock-based compensation expense that is calculated based upon awards ultimately expected to vest and, thus, stock-based compensation expense is reduced for estimated forfeitures. Forfeitures are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. All stock-based compensation for equity awards granted to employees and non-employee directors is measured based on the grant date fair value of the award.

The Company values RSUs at the fair value of the Company’s common stock on the date of grant. Prior to the IPO, the Company estimated the fair value of its common stock utilizing periodic contemporaneous valuations prepared by an independent third-party appraiser based upon several factors, including the Company's operating and financial performance, progress and milestones attained in its business, and past sales of convertible preferred stock. Upon the effectiveness of the IPO, the fair value of the Company's common stock is its closing market price as of the measurement date.

The Company estimates the fair value of each stock option and purchase right under the ESPP granted to employees on the date of grant using the Black-Scholes option-pricing model and using the assumptions noted in the below table. Expected volatility is based upon the historical volatility of a peer group of publicly traded companies. The expected term of options granted is estimated using the simplified method by taking the average of the vesting term and the contractual term of the option. Starting in November 2014, the Company began estimating the expected volatility assumption for purchase rights under the ESPP based on the historical volatility of the Company's common stock as it had then been publicly traded for more than six months (i.e., the expected term of the purchase rights under the ESPP). The risk-free rate for the expected term of the awards is based on U.S. Treasury zero-coupon issues at the time of grant.

The weighted-average assumptions used to value stock options and purchase rights under the ESPP granted during the years ended December 31, 2015, 2014 and 2013 were as follows:



Stock Options	Year Ended December 31,
	2015	2014	2013
Expected term (years)	6.1	6.1	6.0
Volatility	49%	55%	60%
Risk-free interest rate	1.6%	1.8%	1.5%
Dividend yield	—	—	—



ESPP	Granted In
	November 2015	May 2015	November 2014	April 2014
Expected term (years)	0.5	0.5	0.5	0.8
Volatility	54%	43%	56%	39%
Risk-free interest rate	0.3%	0.1%	0.1%	0.1%
Dividend yield	—	—	—	—

Net Loss Per Share

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Net Loss Per Share

9. Net Loss Per Share

Basic net loss per share is calculated by dividing net loss by the weighted average number of shares of common stock outstanding during the period, and excludes any dilutive effects of employee stock-based awards and warrants. Diluted net income per share is computed giving effect to all potentially dilutive common shares, including common stock issuable upon exercise of stock options and warrants and vesting of restricted stock. As the Company had net losses for the years ended December 31, 2015, 2014 and 2013, all potentially issuable common shares were determined to be anti-dilutive.

The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data).



	Year Ended December 31,
	2015			2014			2013
Net loss	$	(25,838	)	$	(37,786	)	$	(31,314	)
Weighted-average shares used in computing basic and diluted net loss per share	50,141			37,604			4,006
Basic and diluted net loss per share	$	(0.52	)	$	(1.00	)	$	(7.82	)

The following securities were excluded from the calculation of diluted net loss per share attributable to common stockholders because their effect would have been anti-dilutive for the periods presented (in thousands).



	December 31,
	2015	2014	2013
Convertible preferred stock	—	—	30,554
Stock options	6,092	7,164	7,633
Restricted stock units	1,818	1,370	—
ESPP	156	192	—
Common stock warrants	191	360	—
Convertible preferred stock warrants	—	—	391
Common stock subject to repurchase or forfeiture	—	59	134
Total	8,257	9,145	38,712

Income Taxes

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Income Taxes

10. Income Taxes

The following table presents components of loss before income taxes for the periods presented (in thousands):



	Year Ended December 31,
	2015			2014			2013
United States	$	(26,305	)	$	(37,657	)	$	(31,628	)
International	528			(44		)	384
Loss before income taxes	$	(25,777	)	$	(37,701	)	$	(31,244	)

Provision for income taxes for the periods presented consisted of (in thousands):



	Year Ended December 31,
	2015		2014		2013
Current:
U.S. federal	$	—	$	—	$	—
U.S. state	21		12		9
Foreign	40		73		61
Total provision for income taxes	$	61	$	85	$	70

Income tax expense differed from the amounts computed by applying the U.S. federal income tax rate of 34% to pre-tax loss for the periods presented as a result of the following (in thousands):



	Year Ended December 31,
	2015			2014			2013
U.S. federal tax at statutory rate	$	(8,764	)	$	(12,818	)	$	(10,623	)
U.S. state income taxes	(756		)	(1,098		)	(786		)
Non-deductible expenses	438			420			1,383
Research and development credit	(440		)	(455		)	(339		)
Stock-based compensation	737			746			444
Other	481			(72		)	(586		)
Change in valuation allowance	8,365			13,362			10,577
Total provision for income taxes	$	61		$	85		$	70

The tax effects of temporary differences that give rise to significant portions of the Company’s deferred tax assets and liabilities as of December 31, 2015 and 2014 related to the following (in thousands):



	December 31,
	2015			2014
Deferred tax assets:
Net operating loss and credit carryforwards	$	45,671		$	39,211
Accrued liabilities	5,488			4,308
Allowance for doubtful accounts	394			256
Accrued compensation	817			626
Intangibles	23			23
Gross deferred tax assets	52,393			44,424
Valuation allowance	(51,568		)	(43,203		)
Net deferred tax assets	825			1,221
Deferred tax liabilities:
Property and equipment	(71		)	(278		)
Amortized intangibles	(754		)	(943		)
Gross deferred tax liabilities	(825		)	(1,221		)
Net deferred taxes	$	—		$	—

The Company has not provided for U.S. income taxes on undistributed earnings of its foreign subsidiaries because it intends to permanently re-invest those earnings outside the United States. As of December 31, 2015, undistributed earnings of the Company's foreign subsidiaries was approximately $0.8 million.

A valuation allowance is provided for deferred tax assets where the recoverability of the assets is uncertain. The determination to provide a valuation allowance is dependent upon the assessment of whether it is more likely than not that sufficient future taxable income will be generated to utilize the deferred tax assets. Based on the weight of the available evidence, which includes the Company’s historical operating losses, lack of taxable income, and the accumulated deficit, for the year ended December 31, 2015, the Company has provided a valuation allowance against its U.S. net deferred tax assets. The net change in the valuation allowance for the years ended December 31, 2015 and 2014 was an increase of $8.4 million and $13.4 million, respectively.

As of December 31, 2015, the Company had net operating loss carry-forwards for federal and state income tax purposes of approximately $124.4 million and $85.2 million, respectively, available to reduce future income subject to income taxes. If not utilized, these carryforwards will begin to expire in 2024 for federal purposes and began to expire in 2015 for state purposes. As of December 31, 2015, the Company also had research credit carryforwards for federal and California state tax purposes of approximately $2.2 million and $1.8 million. If not utilized, the federal research credit carryforwards will begin to expire in 2022. The California state research credits can be carried forward indefinitely. The Internal Revenue Code of 1986, as amended, imposes restrictions on the utilization of net operating losses in the event of an “ownership change” of a corporation. Accordingly, a company’s ability to use net operating losses may be limited as prescribed under the IRC Section 382. Events which may cause limitations in the amount of the net operating losses that the Company may use in any one year include, but are not limited to, a cumulative ownership change of more than 50% over a three-year period. Utilization of the federal and state net operating losses may be subject to substantial annual limitation due to the ownership change limitations provided by the IRC Section 382 and similar state provisions. The Company experienced an ownership change prior to 2014 that did not materially impact the availability of its net operating losses and tax credits and the disclosed amounts of such attributes have been reduced for the effect of the IRC Section 382 limitations. In the event the Company has subsequent changes in ownership in connection with the IPO or other transactions, net operating losses and research and development credit carryforwards, which are fully reserved by the deferred tax asset valuation allowance, could be limited and may expire unutilized.

Unrecognized Tax Benefits

The table below shows the changes in the gross amount of unrecognized tax benefits for the periods presented (in thousands):



	Year Ended December 31,
	2015			2014			2013
Unrecognized benefit — beginning of period	$	1,975		$	1,455		$	1,075
Gross increases — current year tax positions	522			532			382
Gross decreases — prior year tax positions	(12		)	(12		)	(2		)
Unrecognized benefit — end of period	$	2,485		$	1,975		$	1,455

As of December 31, 2015 and 2014, an immaterial amount of the total unrecognized tax benefits, if recognized, would have an impact on the Company’s effective tax rate. The Company recognizes interest and penalties related to uncertain tax positions as income tax expense. The Company does not anticipate that its total unrecognized tax benefits as of December 31, 2015 will significantly change due to settlement of examination or the expiration of statute of limitations during the next 12 months. The Company is currently unaware of any uncertain tax positions that could result in significant additional payments, accruals or other material deviation in this estimate over the next 12 months.

The Company is subject to taxation in the United States, various states and several foreign jurisdictions. Due to the Company’s net carryover of unused operating losses, all years from 2001 forward remain subject to future examination by the U.S. federal and state tax authorities. The Company’s foreign tax returns are open to audit under the statutes of limitations of the respective foreign countries in which the subsidiaries are located. The Company considers all undistributed earnings of its foreign subsidiaries indefinitely reinvested.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

11. Commitments and Contingencies

Leases

The Company has operating lease agreements for offices, research and development, and sales and marketing facilities that expire at various dates through 2018. The Company recognizes rent expense on a straight-line basis over the lease term and records the difference between cash rent payments and the recognized rent expense as a deferred rent liability. Rent expense was $2.0 million, $2.6 million and $2.3 million for the years ended December 31, 2015, 2014 and 2013, respectively.

The Company enters into capital leases to finance data center and other computer and networking equipment.

As of December 31, 2015, approximate remaining future minimum lease payments under non-cancelable leases are as follows (in thousands):



Year Ending December 31,	Capital Leases			Operating Leases
2016	$	6,079		$	2,144
2017	4,289			1,879
2018	779			304
2019	37			—
Total future minimum lease payment	$	11,184		$	4,327
Less — amount representing interest	(1,606		)
Present value of total capital lease obligation	$	9,578
Capital lease obligation — current portion	4,972
Capital lease obligation — net of current portion	4,606

Hosting, Telecommunication Usage and Maintenance Services

The Company has agreements with third parties to provide co-location hosting and telecommunication usage services. The agreements require payments per month for a fixed period of time in exchange for certain guarantees of network and telecommunication availability. The Company is also committed to make future payments under maintenance service contracts for certain data center equipment.

As of December 31, 2015, future minimum payments under these arrangements are as follows (in thousands):



Year Ending December 31,	Hosting Services		Telecommunication Usage Services		Equipment Maintenance Services
2016	$	1,573	$	765	$	332
2017	832		1,036		177
2018	10		4		—
Total future minimum payment	$	2,415	$	1,805	$	509

Universal Services Fund Liability

During the third quarter of 2012, the Company determined that based on its business activities, it is classified as a telecommunications service provider for regulatory purposes and it should make direct contributions to the federal USF and related funds based on revenues it receives from the resale of interstate and international telecommunications services. Previously, the Company had believed that the telecommunications services were an integral part of an information service that the Company provides via its software and had instead made indirect USF contributions via payments to its wholesale telecommunications service providers. In order to comply with the obligation to make direct contributions, the Company made a voluntary self-disclosure to the FCC Enforcement Bureau and registered with the USAC, which is charged by the FCC with administering the USF. The Company filed exemption certificates with its wholesale telecommunications service providers in order to eliminate its obligation to reimburse such wholesale telecommunications service providers for their USF contributions calculated on services sold to the Company.

The Company’s registration with USAC subjects it to assessments for unpaid USF contributions, as well as interest thereon and civil penalties, due to its late registration and past failure to recognize its obligation as a USF contributor and as an international carrier. The Company will be required to pay assessments for periods prior to the Company’s registration. As of December 31, 2012, the total past due USF contribution being imposed by USAC and accrued by the Company for the period from 2003 through 2012 was $8.1 million, of which $4.7 million was undisputed and $3.4 million, including $0.8 million that pertains to 2003 through 2007, was disputed. While the Company is in administrative proceedings before the FCC to limit such back assessments to the period 2008 through 2012, it is possible that it will be required to pay back assessments for the period from 2003 through 2007. In 2013, the Company began remitting required contributions on a prospective basis directly to USAC.

In July 2013, the Company and USAC agreed to a financing arrangement for $4.1 million of the undisputed $4.7 million of the unpaid USF contributions whereby the Company issued to USAC a promissory note payable in the principal amount of the $4.1 million and paid off the remaining undisputed $0.6 million. The repayment terms of the promissory note payable are disclosed in Note 7. As of December 31, 2015 and 2014, the principal balance of the promissory note payable was $1.5 million and $2.6 million, respectively, and is included in the notes payable amounts on the consolidated balance sheets. In addition to the promissory note payable, as of December 31, 2015 and 2014, the Company had an accrued liability for the disputed portion of the unpaid USF contributions and estimated interest and penalties of $4.9 million and $4.2 million, respectively, included in accrued federal fees on the consolidated balance sheets. For the years ended December 31, 2015, 2014 and 2013, the Company recorded interest and penalty expenses of $0.5 million, $0.5 million and $0.2 million, respectively, as a charge to general and administrative expense, which were related to its disputed unpaid USF obligations.

On June 12, 2015, in connection with the Company’s disclosure to the FCC, the Company entered into a consent decree with the FCC Enforcement Bureau. In the consent decree, the Company agreed to pay a civil penalty of $2.0 million to the U.S. Treasury in twelve equal quarterly installments starting in July 2015 without interest (Note 7). In the third quarter of 2014, the Company accrued a $2.0 million liability for the then tentative civil penalty. The consent decree also requires the Company to adopt certain internal regulatory compliance monitoring and training requirements, and to report on the status of those compliance efforts to the FCC’s Enforcement Bureau for three years. The Company’s implementation of the internal regulatory compliance monitoring and training requirements were completed in August 2015, and its annual compliance reporting to the FCC will continue until June 2018.

State and Local Taxes and Surcharges

In April 2012, the Company commenced collecting and remitting sales taxes on sales of subscription services in all the U.S. states in which it determined it was obligated to do so. During the first quarter of 2015, the Company conducted an updated sales tax review of the taxability of sales of its subscription services. As a result, the Company determined that it may be obligated to collect and remit sales taxes on such sales in four additional states. Based on its best estimate of the probable sales tax liability in those four states relating to its sales of subscription services during the period 2011 through 2014, during the three months ended March 31, 2015, the Company recorded a general and administrative expense of $0.6 million as an immaterial out of period adjustment to accrue for such taxes.

During 2013, the Company analyzed its activities and determined it may be obligated to collect and remit various state and local taxes and surcharges on its usage-based fees. The Company had not remitted state and local taxes on usage-based fees in any of the periods prior to 2014 and therefore accrued a sales tax liability for this contingency. In January 2014, the Company commenced paying such taxes and surcharges to certain state authorities. In June 2014, the Company commenced collecting state and local taxes or surcharges on usage-based fees from its clients on a current basis and remitting such taxes to the applicable U.S. state taxing authorities.

During the year ended December 31, 2015, the Company remitted $1.1 million for its contingent sales taxes on both usage-based fees and sales of subscription services. Excluding the credit recorded in 2014 as discussed below, for the years ended December 31, 2015, 2014 and 2013, the Company recognized $1.2 million, $1.1 million and $2.2 million, respectively, as general and administrative expense related to its estimated sales tax liability on both usage-based fees and sales of subscription services in the U.S. and Canada, which was not being collected from its clients.

Reversal of contingent sales tax liability - In May 2014, the Company received a letter from a state revenue authority which concluded that the Company's services provided to customers in that specific state are not subject to that state's local taxes. As a result, the Company released $2.8 million of sales tax liability, including estimated interest charges, accrued progressively on a quarterly basis from 2011 through the first quarter of 2014 for that state. No amounts were billed to and collected from customers for this state during that period. Of the total reversal amount, $2.5 million was related to the period 2011 through 2013. The reversal has been recorded through the general and administrative expense caption in the consolidated statements of operations and comprehensive loss.

As of December 31, 2015, the Company had total accrued liabilities of $2.7 million for such contingent sales taxes and surcharges that were not being collected from its clients but may be imposed by various taxing authorities, of which $0.8 million and $1.9 million was included in current and non-current “Sales tax liability” on the condensed consolidated balance sheets, respectively. As of December 31, 2014, the Company had total accrued liabilities of $2.6 million for such contingent sales taxes and surcharges, which was included in non-current “Sales tax liability” on the consolidated balance sheets. The Company’s estimate of the probable loss incurred under this contingency is based on its analysis of the source location of its usage-based fees and the regulations and rules in each tax jurisdiction.

Legal Matters

The Company is involved in various legal and regulatory matters arising in the normal course of business. In management’s opinion, resolution of these matters is not expected to have a material impact on the Company’s consolidated results of operations, cash flows, or its financial position. However, due to the uncertain nature of legal matters, an unfavorable resolution of a matter could materially affect the Company’s future consolidated results of operations, cash flows or financial position in a particular period.

The Company is currently involved in the following lawsuit as a defendant.

NobelBiz Litigation

On August 5, 2011, NobelBiz sent a letter to the Company asserting infringement of a patent related to virtual call centers. On April 3, 2012, NobelBiz filed a patent infringement lawsuit against the Company in the United States District Court for the Eastern District of Texas. The patent asserted in the complaint is different, but related, to the patent asserted in the original letter. The lawsuit, NobelBiz Inc. v. Five9, Inc., Case No. 6:12-cv-00243-LED, alleges that the Company’s local caller ID management service infringes United States Patent No. 8,135,122, or the ‘122 patent. The ‘122 patent, titled “System and Method for Modifying Communication Information (MCI),” issued on March 13, 2012, and according to the complaint is alleged to relate to “a system for processing a telephone call from a call originator (also referred to as a calling party) to a call target (also referred to as a receiving party), where the system accesses a database storing outgoing telephone numbers, selects a replacement telephone number from the outgoing telephone numbers based on the telephone number of the call target, and originates an outbound call to the call target with a modified outgoing caller identification (‘caller ID’).” NobelBiz seeks damages in the form of lost profits as well as injunctive relief. The lawsuit is one of several lawsuits filed by NobelBiz the same day against various companies including TCN Inc., LiveVox, Inc. and Global Connect LLC. On March 28, 2013, the court granted the Company’s motion to transfer the case to the United States District Court for the Northern District of California. Subsequently, NobelBiz amended its complaint to add claims related to U.S. Patent No. 8,565,399, or the ‘399 patent, which is a continuation in the same family as the ‘122 patent and addresses the same technology. The Company responded to the complaint and amended complaint by asserting noninfringement and invalidity of the ‘122 and ‘399 patents. On January 16, 2015, the court issued an order regarding claim construction of the two patents-in-suit. A further case management conference has been scheduled for March 7, 2016, at which point it is anticipated that the Court will set additional dates, including dates for hearing summary judgment motions and for trial.

The Company has investigated the claims alleged in the complaint and believes that it has good defenses to the claims. While the Company does not believe that it is probable that a loss has been incurred, the ultimate resolution of the matter could potentially result in a loss. Management’s best estimate of the low end of the range of the potential loss is zero. At this time, it is not possible to reasonably estimate the high end of the range of the potential loss, which could be material to the Company’s results of operations. Accordingly, the Company has not accrued a loss related to this matter as the Company.

Indemnification Agreements

In the ordinary course of business, the Company may provide indemnifications of varying scope and terms to clients, vendors, lessors, business partners and other parties with respect to certain matters, including, but not limited to, losses arising out of breach of such agreements, services to be provided by the Company or from intellectual property infringement claims made by third parties. In addition, the Company has entered into indemnification agreements with its directors, officers and certain employees that require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors, officers or employees. No demands have been made upon the Company to provide indemnification under such agreements and thus there are no claims that the Company is aware of that would have a material effect on the Company’s consolidated balance sheets, consolidated statements of operations and comprehensive loss, or consolidated statements of cash flows.

Geographical Information

12 Months Ended

Dec. 31, 2015

Segment Reporting [Abstract]

Geographical Information

12. Geographical Information

The following table is a summary of revenues by geographic region based on client billing address and has been estimated based on the amounts billed to clients during the periods (in thousands).



	Year Ended December 31,
	2015		2014		2013
United States	$	120,037	$	95,345	$	75,374
International	8,831		7,757		8,758
Total revenue	$	128,868	$	103,102	$	84,132

The following table summarizes total property and equipment, net in the respective locations (in thousands).



	December 31,
	2015		2014		2013
United States	$	10,939	$	10,625	$	11,079
International	2,286		1,946		528
Property and equipment, net	$	13,225	$	12,571	$	11,607

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Retirement Plans	12 Months Ended
Retirement Plans	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Retirement Plans	13. Retirement Plans The Company has a 401(k) plan to provide tax deferred salary deductions for all eligible employees. Participants may make voluntary contributions to the 401(k) plan, limited by certain Internal Revenue Service restrictions. The Company is responsible for the administrative costs of the 401(k) plan. The Company does not match employee contributions.

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Selected Quarterly Financial Data (Unaudited)

14. Selected Quarterly Financial Data (Unaudited)

Selected quarterly financial information for 2015 and 2014 is as follows:



	Quarter Ended
	Dec. 31, 2015			Sept. 30, 2015			Jun. 30, 2015			Mar. 31, 2015			Dec. 31, 2014			Sept. 30, 2014 (1)			Jun. 30, 2014 (2)			Mar. 31, 2014

	(unaudited, in thousands, except per share data)
Revenue	$	36,033		$	32,287		$	30,274		$	30,274		$	28,274		$	25,869		$	24,685		$	24,274
Cost of revenue ⁽³⁾⁽⁴⁾	15,635			14,812			14,270			14,778			14,540			13,504			13,469			13,148
Gross profit	20,398			17,475			16,004			15,496			13,734			12,365			11,216			11,126
Operating expenses:
Research and development ⁽³⁾⁽⁴⁾	5,580			5,473			5,568			6,038			5,828			5,503			5,554			5,225
Sales and marketing ⁽³⁾⁽⁴⁾	10,720			10,797			10,594			9,931			9,453			9,296			9,674			9,022
General and administrative ⁽³⁾⁽⁴⁾	6,433			6,087			6,027			7,275			6,763			7,967			3,515			6,171
Total operating expenses	22,733			22,357			22,189			23,244			22,044			22,766			18,743			20,418
Loss from operations	(2,335		)	(4,882		)	(6,185		)	(7,748		)	(8,310		)	(10,401		)	(7,527		)	(9,292		)
Other income (expense), net:
Interest expense	(1,198		)	(1,235		)	(1,155		)	(1,139		)	(1,175		)	(1,116		)	(1,092		)	(778		)
Interest income and other	28			119			(49		)	2			146			95			(28		)	32
Change in fair value of convertible preferred and common stock warrant liabilities	—			—			—			—			—			—			—			1,745
Total other income (expense), net	(1,170		)	(1,116		)	(1,204		)	(1,137		)	(1,029		)	(1,021		)	(1,120		)	999
Loss before income taxes	(3,505		)	(5,998		)	(7,389		)	(8,885		)	(9,339		)	(11,422		)	(8,647		)	(8,293		)
Provision for (benefit from) income taxes	13			50			(20		)	18			33			13			12			27
Net loss	$	(3,518	)	$	(6,048	)	$	(7,369	)	$	(8,903	)	$	(9,372	)	$	(11,435	)	$	(8,659	)	$	(8,320	)
Net loss per share:
Basic and diluted	$	(0.07	)	$	(0.12	)	$	(0.15	)	$	(0.18	)	$	(0.19	)	$	(0.24	)	$	(0.18	)	$	(1.48	)
Shares used in computing net loss per share:
Basic and diluted	50,764			50,369			49,980			49,433			49,003			48,310			46,898			5,608

(1) General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.

(2) General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

(3) Included stock-based compensation as follows:



	Quarter Ended
	Dec. 31, 2015		Sept. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sept. 30, 2014		Jun. 30, 2014		Mar. 31, 2014

	(unaudited, in thousands)
Cost of revenue	$	227	$	233	$	218	$	188	$	176	$	158	$	121	$	87
Research and development	401		475		340		574		527		583		471		350
Sales and marketing	370		448		458		524		455		361		368		326
General and administrative	722		789		814		949		799		775		763		433
Total stock-based compensation	$	1,720	$	1,945	$	1,830	$	2,235	$	1,957	$	1,877	$	1,723	$	1,196

(4) Included depreciation and amortization expenses as follows:



	Quarter Ended
	Dec. 31, 2015		Sept. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sept. 30, 2014		Jun. 30, 2014		Mar. 31, 2014

	(unaudited, in thousands)
Cost of revenue	$	1,483	$	1,470	$	1,558	$	1,439	$	1,291	$	1,272	$	1,373	$	1,202
Research and development	140		126		102		87		75		58		50		46
Sales and marketing	54		52		51		49		50		50		48		48
General and administrative	186		192		199		200		189		187		228		296
Total depreciation and amortization	$	1,863	$	1,840	$	1,910	$	1,775	$	1,605	$	1,567	$	1,699	$	1,592

Description of Business and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Basis of Presentation

Use of Estimates

Foreign Currency

Cash and Cash Equivalents

Short-Term Investments

Concentration Risks

Allowance for Doubtful Accounts

The following table presents the changes in the allowance for doubtful accounts (in thousands):



	Year Ended December 31,
	2015			2014			2013
Balance, beginning of period	$	65		$	42		$	54
Add: bad debt expense	171			76			89
Less: write-offs, net of recoveries	(221		)	(53		)	(101		)
Balance, end of period	$	15		$	65		$	42

Property and Equipment, Net

Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows:



Asset Category		Estimated Useful Lives
Computer and network equipment		3 years
Computer software		3 years
Development costs		1 to 5 years
Furniture and fixtures		7 years
Leasehold improvements		Shorter of useful life or lease term

Business Combinations

Goodwill and Intangible Assets

Revenue Recognition

The Company recognizes revenue for each unit of accounting when all of the following criteria have been met:


•	persuasive evidence of an arrangement exists;


•	delivery has occurred;


•	the fee is fixed or determinable; and


•	collection is reasonably assured.

Revenue allocated to the separate accounting units is recognized as follows:


•	fixed subscription revenue is recognized on a straight-line basis over the applicable term, predominantly the monthly contractual billing period;


•	variable usage revenue is recognized as actual usage occurs. Usage revenue in subscription arrangements that include bundled usage is recognized on a straight-line basis over the applicable term, as the Company cannot reliably estimate client usage patterns; and


•	professional services revenue is recognized as services are performed using the proportional performance method, with performance measured based on labor hours, assuming all other revenue recognition criteria have been met.

Deferred Revenue

Cost of Revenue

Research and Development

Advertising Costs

Commissions

Stock-Based Compensation

Convertible Preferred and Common Stock Warrant Liabilities

Recent Accounting Pronouncements

Recently Adopted Accounting Pronouncement

Recent Accounting Pronouncement Not Yet Effective

Description of Business and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Allowance for Doubtful Accounts

The following table presents the changes in the allowance for doubtful accounts (in thousands):



	Year Ended December 31,
	2015			2014			2013
Balance, beginning of period	$	65		$	42		$	54
Add: bad debt expense	171			76			89
Less: write-offs, net of recoveries	(221		)	(53		)	(101		)
Balance, end of period	$	15		$	65		$	42

Schedule of Property and Equipment, Useful Lives

Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows:



Asset Category		Estimated Useful Lives
Computer and network equipment		3 years
Computer software		3 years
Development costs		1 to 5 years
Furniture and fixtures		7 years
Leasehold improvements		Shorter of useful life or lease term

Property and equipment, net consisted of the following (in thousands):



	December 31,
	2015			2014
Computer and network equipment	$	30,277		$	24,292
Computer software	3,566			2,264
Internal-use software development costs	128			—
Furniture and fixtures	1,113			1,030
Leasehold improvements	619			611
Property and equipment	35,703			28,197
Accumulated depreciation and amortization	(22,478		)	(15,626		)
Property and equipment, net	$	13,225		$	12,571

Acquisition of Face It, Corp. (Tables)

12 Months Ended

Dec. 31, 2015

Business Combinations [Abstract]

Schedule of Fair Value of Assets Acquired and Liabilities Assumed

The following table summarizes the fair values of the assets acquired and liabilities assumed at the Acquisition Date (in thousands):



	As of October 18, 2013
Tangible assets acquired	$	177
Intangible assets:
Developed technology	2,460
Customer relationships	520
Domain names	50
Non-compete agreements	140
Goodwill	11,798
Current liabilities	(113		)
Total purchase price	$	15,032

Schedule of Estimated Useful Lives and Valuation Techniques

Details related to estimated useful lives and the valuation techniques utilized for estimating fair value of the intangible assets acquired are shown below:



Intangible Type	Valuation Technique	Useful Life
Developed technology	Excess earnings method	7 years
Customer relationships	Cost approach	5 years
Domain names	Relief from royalty method	5 years
Non-compete agreements	Modified discounted cash flow	3 years

Schedule of Pro Forma Financial information



	2013
Revenue	$	84,260
Net loss	$	(32,787	)

Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2015

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Carried at Fair Value

The fair value of assets and liabilities carried at fair value was determined using the following inputs (in thousands):



	December 31, 2015
	Total		Level 1
Assets
Cash equivalents:
Money market funds	$	20,010	$	20,010

	December 31, 2014
	Total		Level 1
Assets
Short-term investments:
U.S. Treasury bills	$	20,000	$	20,000

Cash, Cash Equivalents and Short-Term Investments (Tables)

12 Months Ended

Dec. 31, 2015

Cash, Cash Equivalents, and Short-term Investments [Abstract]

Schedule of Cash and Cash Equivalents

Cash and cash equivalents consisted of the following (in thousands):



	December 31,
	2015		2014
Cash and cash equivalents:
Cash	$	38,474	$	58,289
Money market funds	20,010		—
Total cash and cash equivalents	$	58,484	$	58,289

Schedule of Short-Term Investments

As of December 31, 2014, short-term investments consisted of the following (in thousands):



	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Aggregate Fair Value
U.S. Treasury bills	$	20,000	$	—	$	—	$	20,000

- Definition

Tabular disclosure of available-for-sale securities which includes, but is not limited to, changes in the cost basis and fair value, fair value and gross unrealized gain (loss), fair values by type of security, contractual maturity and classification, amortized cost basis, contracts to acquire securities to be accounted for as available-for-sale, debt maturities, transfers to trading, change in net unrealized holding gain (loss) net of tax, continuous unrealized loss position fair value, aggregate losses qualitative disclosures, other than temporary impairment (OTTI) losses or other disclosures related to available for sale securities.

+ References + Details

Financial Statement Components (Tables)

12 Months Ended

Dec. 31, 2015

Financial Statement Components [Abstract]

Schedule of Accounts Receivable

Accounts receivable, net consisted of the following (in thousands):



	December 31,
	2015			2014
Trade accounts receivable	$	9,554		$	7,482
Unbilled trade accounts receivable, net of advance client deposits	1,028			918
Allowance for doubtful accounts	(15		)	(65		)
Accounts receivable, net	$	10,567		$	8,335

Schedule of Property and Equipment

Property and equipment is stated at cost less accumulated depreciation and amortization, and is depreciated using the straight-line method over the estimated useful lives of the assets as follows:



Asset Category		Estimated Useful Lives
Computer and network equipment		3 years
Computer software		3 years
Development costs		1 to 5 years
Furniture and fixtures		7 years
Leasehold improvements		Shorter of useful life or lease term

Property and equipment, net consisted of the following (in thousands):



	December 31,
	2015			2014
Computer and network equipment	$	30,277		$	24,292
Computer software	3,566			2,264
Internal-use software development costs	128			—
Furniture and fixtures	1,113			1,030
Leasehold improvements	619			611
Property and equipment	35,703			28,197
Accumulated depreciation and amortization	(22,478		)	(15,626		)
Property and equipment, net	$	13,225		$	12,571

Schedule of Capital Leased Property and Equipment

Property and equipment capitalized under capital lease obligations consist primarily of computer and network equipment and were as follows (in thousands):



	December 31,
	2015			2014
Gross	$	27,302		$	21,025
Less: accumulated depreciation and amortization	(16,429		)	(10,609		)
Total	$	10,873		$	10,416

Schedule of Accrued and Other Current Liabilities

Accrued and other current liabilities consisted of the following (in thousands):



	December 31,
	2015		2014
Accrued expenses	$	2,193	$	2,240
Accrued compensation and benefits	5,718		5,078
Accrued and other current liabilities	$	7,911	$	7,318

Goodwill and Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Intangible Assets

The components of intangible assets are as follows (in thousands):



	December 31, 2015							December 31, 2014
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
Developed technology	$	2,460	$	(775	)	$	1,685	$	2,460	$	(423	)	$	2,037
Customer relationships	520		(229		)	291		520		(125		)	395
Domain names	50		(22		)	28		50		(12		)	38
Non-compete agreements	140		(103		)	37		140		(57		)	83
Total	$	3,170	$	(1,129	)	$	2,041	$	3,170	$	(617	)	$	2,553

Schedule of Expected Future Amortization Expense of Intangible Assets

As of December 31, 2015, the expected future amortization expense for intangible assets was as follows (in thousands):



Period	Expected Future Amortization Expense
2016	$	503
2017	465
2018	442
2019	351
2020	280
Total	$	2,041

Debt (Tables)

12 Months Ended

Dec. 31, 2015

Debt Disclosure [Abstract]

Schedule of Debt

As of December 31, 2015 and 2014, the Company’s outstanding debt is summarized as follows (in thousands):



	December 31,
	2015			2014
Term loan under 2014 Loan and Security Agreement	$	20,000		$	20,000
Term loan under 2013 Loan and Security Agreement	2,500			4,500
Promissory note to USAC	1,459			2,640
FCC civil penalty	1,667			—
Total notes payable, gross	25,626			27,140
Less: discount	(1,087		)	(1,216		)
Total notes payable, net carrying value	24,539			25,924
Revolving line of credit	12,500			12,500
Total debt, net carrying value	$	37,039		$	38,424
Less: current portion of debt *	(19,712		)	(3,146		)
Total debt, less current portion **	17,327			35,278


* Included in ‘Revolving line of credit’ and ‘Notes payable’ in the consolidated balance sheets.
** Included in ‘Notes payable - less current portion’ and ‘Revolving line of credit - less current portion’ in the consolidated balance sheets.

Schedule of Maturities of Debt

Maturities of the Company’s outstanding debt as of December 31, 2015 are as follows (in thousands):



Period	Amount to Mature
2016	$	20,173
2017	5,286
2018	4,334
2019	8,333
Total	$	38,126

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21538-112644

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21506-112644

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28541-108399

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21521-112644

+ Details

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Schedule of Warrant Disclosures

As of December 31, 2015, the Company had outstanding warrants to purchase shares of common stock as follows (in thousands, except per share data):



Expiration Date	Exercise Price		Warrants Outstanding at December 31, 2015
October 2023	$	5.76	13
February 2024	$	10.12	178
Total			191

The table below is a summary of the Company’s common stock warrant activity during the year ended December 31, 2015 (in thousands, except per share data).



	Shares			Weighted Average Exercise Price
Outstanding as of December 31, 2014	360			$	5.59
Issued	—			—
Exercised	(169	)	(1)	0.65
Outstanding as of December 31, 2015	191			$	9.96

Schedule of Valuation Assumptions, Warrants



	IPO Date April 3, 2014			December 31, 2013
Fair value of Series A-2 preferred stock	$	1.75	(1)	$	2.69	(2)
Fair value of Series D-2 preferred stock	$	1.75	(1)	$	2.81	(2)
Fair value of common stock	$	7.00	(1)	*
Risk-free interest rate	0.13% to 2.73%			0.33% to 2.60%
Expected life	Remaining contractual life			Remaining contractual life
Expected dividends	—			—
Volatility	40% - 50%			45 %


(1) Fair value of the underlying stock is based on the Company's IPO price of $7.00 per share calculated on a pre-reverse split basis for preferred stock and post-reverse split basis for common stock.
(2) The per share data is on a pre-reverse split basis for preferred stock.
* There were no liability-classified common stock warrants at December 31, 2013.

Schedule of Common Stock Reserved for Future Issuance

As of December 31, 2015, shares of common stock reserved for future issuance related to outstanding equity awards, warrants, and employee equity incentive plans were as follows (in thousands):



		December 31, 2015
Stock options outstanding		6,092
Restricted stock units outstanding		1,818
Shares available for future grant under 2014 Plan		5,079
Shares available for future issuance under ESPP		911
Common stock warrants outstanding		191
Total shares of common stock reserved		14,091

Schedule of Stock Option Activities

A summary of the Company’s stock option activity during the year ended December 31, 2015 is as follows (in thousands, except years and per share data):



	Number of Shares		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (1)
Outstanding as of December 31, 2014	7,164		$	4.34
Options granted	244		4.99
Options exercised	(840	)	1.51
Options forfeited or expired	(476	)	6.67
Outstanding as of December 31, 2015	6,092		$	4.58	6.4	$	27,243
Vested and expected to vest as of December 31, 2015	5,998		4.54		6.4	27,011
Exercisable as of December 31, 2015	4,057		3.55		5.5	22,004


(1) The aggregate intrinsic value amounts are computed based on the difference between the exercise price of the stock options and the fair market value of the Company’s common stock of $8.70 per share as of December 31, 2015 for all in-the-money stock options outstanding.

Following is additional information pertaining to the Company’s stock option activities (in thousands):



	Year Ended December 31,
	2015		2014		2013
Weighted-average grant date fair value per share of options granted	$	2.38	$	3.42	$	4.19
Grant-date fair value of options vested	4,824		3,847		1,417
Intrinsic value of options exercised ⁽¹⁾	3,233		9,808		2,145
Proceeds received from options exercised	1,268		1,127		702


(1) Intrinsic value of options exercised is the difference between the fair market value of the Company’s common stock at the time of exercise and the exercise price paid.

Schedule of RSU Activities

A summary of RSU activity during the year ended December 31, 2015 is as follows (in thousands, except years and per share data):



	Number of Shares		Weighted Average Grant Date Fair Value Per Share
Outstanding as of December 31, 2014	1,370		$	5.21
RSUs granted	1,202		5.10
RSUs vested and released	(566	)	5.73
RSUs forfeited	(188	)	4.94
Outstanding as of December 31, 2015	1,818		$	5.01

Schedule of Stock-based Compensation Expense

Stock-based compensation expenses for the years ended December 31, 2015, 2014 and 2013 were as follows (in thousands):



	Year Ended December 31,
	2015		2014		2013
Cost of revenue	$	866	$	542	$	194
Research and development	1,790		1,931		499
Sales and marketing	1,800		1,510		751
General and administrative	3,274		2,770		505
Total stock-based compensation	$	7,730	$	6,753	$	1,949



	Stock Option		RSU		ESPP
Unrecognized stock-based compensation expense	$	6,983	$	7,280	$	202
Weighted-average amortization period	2.1 years		3.0 years		0.4 years

Schedule of Valuation Assumptions, Stock Option and ESPP

The weighted-average assumptions used to value stock options and purchase rights under the ESPP granted during the years ended December 31, 2015, 2014 and 2013 were as follows:



Stock Options	Year Ended December 31,
	2015	2014	2013
Expected term (years)	6.1	6.1	6.0
Volatility	49%	55%	60%
Risk-free interest rate	1.6%	1.8%	1.5%
Dividend yield	—	—	—



ESPP	Granted In
	November 2015	May 2015	November 2014	April 2014
Expected term (years)	0.5	0.5	0.5	0.8
Volatility	54%	43%	56%	39%
Risk-free interest rate	0.3%	0.1%	0.1%	0.1%
Dividend yield	—	—	—	—

- Definition

Tabular disclosure of warrants or rights issued. Warrants and rights outstanding are derivative securities that give the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. Warrants are often included in a new debt issue to entice investors by a higher return potential. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months. Disclose the title of issue of securities called for by warrants and rights outstanding, the aggregate amount of securities called for by warrants and rights outstanding, the date from which the warrants or rights are exercisable, and the price at which the warrant or right is exercisable.

+ References + Details

Net Loss Per Share (Tables)

12 Months Ended

Dec. 31, 2015

Earnings Per Share [Abstract]

Basic and Diluted Net Loss Per Share

The following table presents the calculation of basic and diluted net loss per share (in thousands, except per share data).



	Year Ended December 31,
	2015			2014			2013
Net loss	$	(25,838	)	$	(37,786	)	$	(31,314	)
Weighted-average shares used in computing basic and diluted net loss per share	50,141			37,604			4,006
Basic and diluted net loss per share	$	(0.52	)	$	(1.00	)	$	(7.82	)

Schedule of Antidilutive Securities Excluded from Computation of Net Loss Per Share



	December 31,
	2015	2014	2013
Convertible preferred stock	—	—	30,554
Stock options	6,092	7,164	7,633
Restricted stock units	1,818	1,370	—
ESPP	156	192	—
Common stock warrants	191	360	—
Convertible preferred stock warrants	—	—	391
Common stock subject to repurchase or forfeiture	—	59	134
Total	8,257	9,145	38,712

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Disclosure [Abstract]

Schedule of Components of Loss before Income Taxes

The following table presents components of loss before income taxes for the periods presented (in thousands):



	Year Ended December 31,
	2015			2014			2013
United States	$	(26,305	)	$	(37,657	)	$	(31,628	)
International	528			(44		)	384
Loss before income taxes	$	(25,777	)	$	(37,701	)	$	(31,244	)

Schedule of Components of Provision for Income Taxes

Provision for income taxes for the periods presented consisted of (in thousands):



	Year Ended December 31,
	2015		2014		2013
Current:
U.S. federal	$	—	$	—	$	—
U.S. state	21		12		9
Foreign	40		73		61
Total provision for income taxes	$	61	$	85	$	70

Schedule of Effective Income Tax Amount Reconciliation

Income tax expense differed from the amounts computed by applying the U.S. federal income tax rate of 34% to pre-tax loss for the periods presented as a result of the following (in thousands):



	Year Ended December 31,
	2015			2014			2013
U.S. federal tax at statutory rate	$	(8,764	)	$	(12,818	)	$	(10,623	)
U.S. state income taxes	(756		)	(1,098		)	(786		)
Non-deductible expenses	438			420			1,383
Research and development credit	(440		)	(455		)	(339		)
Stock-based compensation	737			746			444
Other	481			(72		)	(586		)
Change in valuation allowance	8,365			13,362			10,577
Total provision for income taxes	$	61		$	85		$	70

Schedule of Deferred Tax Assets and Liabilities



	December 31,
	2015			2014
Deferred tax assets:
Net operating loss and credit carryforwards	$	45,671		$	39,211
Accrued liabilities	5,488			4,308
Allowance for doubtful accounts	394			256
Accrued compensation	817			626
Intangibles	23			23
Gross deferred tax assets	52,393			44,424
Valuation allowance	(51,568		)	(43,203		)
Net deferred tax assets	825			1,221
Deferred tax liabilities:
Property and equipment	(71		)	(278		)
Amortized intangibles	(754		)	(943		)
Gross deferred tax liabilities	(825		)	(1,221		)
Net deferred taxes	$	—		$	—

Schedule of Unrecognized Tax Benefits Rollforward

The table below shows the changes in the gross amount of unrecognized tax benefits for the periods presented (in thousands):



	Year Ended December 31,
	2015			2014			2013
Unrecognized benefit — beginning of period	$	1,975		$	1,455		$	1,075
Gross increases — current year tax positions	522			532			382
Gross decreases — prior year tax positions	(12		)	(12		)	(2		)
Unrecognized benefit — end of period	$	2,485		$	1,975		$	1,455

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2015

Commitments and Contingencies Disclosure [Abstract]

Schedule of Future Minimum Lease Payments

As of December 31, 2015, approximate remaining future minimum lease payments under non-cancelable leases are as follows (in thousands):



Year Ending December 31,	Capital Leases			Operating Leases
2016	$	6,079		$	2,144
2017	4,289			1,879
2018	779			304
2019	37			—
Total future minimum lease payment	$	11,184		$	4,327
Less — amount representing interest	(1,606		)
Present value of total capital lease obligation	$	9,578
Capital lease obligation — current portion	4,972
Capital lease obligation — net of current portion	4,606

Schedule of Future Minimum Payments under Hosting, Telecommunication Usage and Maintenance Service Agreements

As of December 31, 2015, future minimum payments under these arrangements are as follows (in thousands):



Year Ending December 31,	Hosting Services		Telecommunication Usage Services		Equipment Maintenance Services
2016	$	1,573	$	765	$	332
2017	832		1,036		177
2018	10		4		—
Total future minimum payment	$	2,415	$	1,805	$	509

Geographical Information (Tables)

12 Months Ended

Dec. 31, 2015

Segment Reporting [Abstract]

Schedule of Revenues and Property and Equipment by Geographic Region

The following table is a summary of revenues by geographic region based on client billing address and has been estimated based on the amounts billed to clients during the periods (in thousands).



	Year Ended December 31,
	2015		2014		2013
United States	$	120,037	$	95,345	$	75,374
International	8,831		7,757		8,758
Total revenue	$	128,868	$	103,102	$	84,132

The following table summarizes total property and equipment, net in the respective locations (in thousands).



	December 31,
	2015		2014		2013
United States	$	10,939	$	10,625	$	11,079
International	2,286		1,946		528
Property and equipment, net	$	13,225	$	12,571	$	11,607

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Financial Information Disclosure [Abstract]

Schedule of Quarterly Financial Information

Selected quarterly financial information for 2015 and 2014 is as follows:



	Quarter Ended
	Dec. 31, 2015			Sept. 30, 2015			Jun. 30, 2015			Mar. 31, 2015			Dec. 31, 2014			Sept. 30, 2014 (1)			Jun. 30, 2014 (2)			Mar. 31, 2014

	(unaudited, in thousands, except per share data)
Revenue	$	36,033		$	32,287		$	30,274		$	30,274		$	28,274		$	25,869		$	24,685		$	24,274
Cost of revenue ⁽³⁾⁽⁴⁾	15,635			14,812			14,270			14,778			14,540			13,504			13,469			13,148
Gross profit	20,398			17,475			16,004			15,496			13,734			12,365			11,216			11,126
Operating expenses:
Research and development ⁽³⁾⁽⁴⁾	5,580			5,473			5,568			6,038			5,828			5,503			5,554			5,225
Sales and marketing ⁽³⁾⁽⁴⁾	10,720			10,797			10,594			9,931			9,453			9,296			9,674			9,022
General and administrative ⁽³⁾⁽⁴⁾	6,433			6,087			6,027			7,275			6,763			7,967			3,515			6,171
Total operating expenses	22,733			22,357			22,189			23,244			22,044			22,766			18,743			20,418
Loss from operations	(2,335		)	(4,882		)	(6,185		)	(7,748		)	(8,310		)	(10,401		)	(7,527		)	(9,292		)
Other income (expense), net:
Interest expense	(1,198		)	(1,235		)	(1,155		)	(1,139		)	(1,175		)	(1,116		)	(1,092		)	(778		)
Interest income and other	28			119			(49		)	2			146			95			(28		)	32
Change in fair value of convertible preferred and common stock warrant liabilities	—			—			—			—			—			—			—			1,745
Total other income (expense), net	(1,170		)	(1,116		)	(1,204		)	(1,137		)	(1,029		)	(1,021		)	(1,120		)	999
Loss before income taxes	(3,505		)	(5,998		)	(7,389		)	(8,885		)	(9,339		)	(11,422		)	(8,647		)	(8,293		)
Provision for (benefit from) income taxes	13			50			(20		)	18			33			13			12			27
Net loss	$	(3,518	)	$	(6,048	)	$	(7,369	)	$	(8,903	)	$	(9,372	)	$	(11,435	)	$	(8,659	)	$	(8,320	)
Net loss per share:
Basic and diluted	$	(0.07	)	$	(0.12	)	$	(0.15	)	$	(0.18	)	$	(0.19	)	$	(0.24	)	$	(0.18	)	$	(1.48	)
Shares used in computing net loss per share:
Basic and diluted	50,764			50,369			49,980			49,433			49,003			48,310			46,898			5,608

(1) General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.

(2) General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

(3) Included stock-based compensation as follows:



	Quarter Ended
	Dec. 31, 2015		Sept. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sept. 30, 2014		Jun. 30, 2014		Mar. 31, 2014

	(unaudited, in thousands)
Cost of revenue	$	227	$	233	$	218	$	188	$	176	$	158	$	121	$	87
Research and development	401		475		340		574		527		583		471		350
Sales and marketing	370		448		458		524		455		361		368		326
General and administrative	722		789		814		949		799		775		763		433
Total stock-based compensation	$	1,720	$	1,945	$	1,830	$	2,235	$	1,957	$	1,877	$	1,723	$	1,196

(4) Included depreciation and amortization expenses as follows:



	Quarter Ended
	Dec. 31, 2015		Sept. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sept. 30, 2014		Jun. 30, 2014		Mar. 31, 2014

	(unaudited, in thousands)
Cost of revenue	$	1,483	$	1,470	$	1,558	$	1,439	$	1,291	$	1,272	$	1,373	$	1,202
Research and development	140		126		102		87		75		58		50		46
Sales and marketing	54		52		51		49		50		50		48		48
General and administrative	186		192		199		200		189		187		228		296
Total depreciation and amortization	$	1,863	$	1,840	$	1,910	$	1,775	$	1,605	$	1,567	$	1,699	$	1,592

Description of Business and Summary of Significant Accounting Policies - Concentration Risks (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash, uninsured amount	$ 58.0	$ 58.0
Concentration Risk, Accounts Receivable	no single client represented more than 10% of accounts receivable	no single client represented more than 10% of accounts receivable
Concentration Risk, Revenue	no single client represented more than 10% of revenue	no single client represented more than 10% of revenue	no single client represented more than 10% of revenue

Description of Business and Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance, beginning of period	$ 65	$ 42	$ 54
Add: bad debt expense	171	76	89
Less: write-offs, net of recoveries	(221)	(53)	(101)
Balance, end of period	$ 15	$ 65	$ 42

Description of Business and Summary of Significant Accounting Policies - Property and Equipment, Net (Details)	12 Months Ended
	Dec. 31, 2015
Computer and Network Equipment
Property, Plant and Equipment [Line Items]
Useful life, in years	3 years
Computer Software
Property, Plant and Equipment [Line Items]
Useful life, in years	3 years
Development Costs \| Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life, in years	1 year
Development Costs \| Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life, in years	5 years
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life, in years	7 years
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Useful life	Shorter of useful life or lease term

Description of Business and Summary of Significant Accounting Policies - Goodwill and Intangible Assets (Details)	12 Months Ended
	Dec. 31, 2015
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-live intangible asset, useful life	3 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-live intangible asset, useful life	7 years

Description of Business and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
USF contributions and other regulatory costs	$ 6.2	$ 4.4	$ 3.9

Description of Business and Summary of Significant Accounting Policies - Advertising Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Advertising expense	$ 9.2	$ 8.7	$ 7.3

Description of Business and Summary of Significant Accounting Policies - Commissions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Commission expense	$ 7.2	$ 6.4	$ 4.8

Acquisition of Face It, Corp. (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Oct. 18, 2013

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1]

Jun. 30, 2014

^[2]

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Business Acquisition [Line Items]

Revenue

$ 36,033

$ 32,287

$ 30,274

$ 28,274

$ 25,869

$ 24,685

$ 24,274

$ 128,868

$ 103,102

$ 84,132

Operating expenses

$ 22,733

$ 22,357

$ 22,189

$ 23,244

$ 22,044

$ 22,766

$ 18,743

$ 20,418

$ 90,523

$ 83,971

63,647

Face It, Corp.

Business Acquisition [Line Items]

Consideration transferred

$ 15,000

Cash paid for acquisition

$ 3,000

Revenue

Operating expenses

800

Acquisition related costs

$ 600

Face It, Corp. | Restricted Common Stock

Business Acquisition [Line Items]

Restricted common stock granted

118,577

Face It, Corp. | Equity Option

Business Acquisition [Line Items]

Shares issued in acquisition (in shares)

22,000

Value of shares issued in acquisition

$ 100

Face It, Corp. | Equity Option | Allocated to Purchase Price

Business Acquisition [Line Items]

Value of shares issued in acquisition

Face It, Corp. | Equity Option | Allocated to Post Combination and Stock Based Compensation

Business Acquisition [Line Items]

Value of shares issued in acquisition

$ 100

Face It, Corp. | Common Stock

Business Acquisition [Line Items]

Shares issued in acquisition (in shares)

1,423,000

Value of shares issued in acquisition

$ 12,100

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

Acquisition of Face it, Corp. - Schedule of Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Oct. 18, 2013
Business Acquisition [Line Items]
Goodwill	$ 11,798	$ 11,798
Face It, Corp.
Business Acquisition [Line Items]
Tangible assets acquired			$ 177
Fair value of intangible assets acquired			3,200
Goodwill			11,798
Current liabilities			(113)
Total purchase price			15,032
Face It, Corp. \| Developed Technology
Business Acquisition [Line Items]
Fair value of intangible assets acquired			2,460
Face It, Corp. \| Customer Relationships
Business Acquisition [Line Items]
Fair value of intangible assets acquired			520
Face It, Corp. \| Domain Names
Business Acquisition [Line Items]
Fair value of intangible assets acquired			50
Face It, Corp. \| Noncompete Agreements
Business Acquisition [Line Items]
Fair value of intangible assets acquired			$ 140

Acquisition of Face It, Corp. - Schedule of Estimated Useful Lives and Valuation Techniques (Details)	12 Months Ended
	Dec. 31, 2015
Developed Technology
Property, Plant and Equipment [Line Items]
Finite-live intangible asset, useful life	7 years
Customer Relationships
Property, Plant and Equipment [Line Items]
Finite-live intangible asset, useful life	5 years
Domain Names
Property, Plant and Equipment [Line Items]
Finite-live intangible asset, useful life	5 years
Noncompete Agreements
Property, Plant and Equipment [Line Items]
Finite-live intangible asset, useful life	3 years

Acquisition of Face It, Corp. - Schedule of Pro Forma Financial Information (Details) - Face It, Corp. $ in Thousands	12 Months Ended
	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Revenue	$ 84,260
Net loss	$ (32,787)

Fair Value Measurements (Details) $ in Millions	Oct. 18, 2013 USD ($)
Face It, Corp.
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of intangible assets acquired	$ 3.2

Fair Value Measurements - Schedule of Assets and Liabilities Carried at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Money Market Funds
Assets
Cash equivalents	$ 20,010
Money Market Funds \| Level 1
Assets
Cash equivalents	$ 20,010
U.S. Treasury bills
Assets
Short-term Investments		$ 20,000
U.S. Treasury bills \| Level 1
Assets
Short-term Investments		$ 20,000

Cash, Cash Equivalents and Short-Term Investments (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents
Restricted cash		$ 800,000
Letter Of Credit Related To Lease Obligation \| Other Noncurrent Assets
Cash and Cash Equivalents
Restricted cash		700,000
Letter Of Credit Related To Insurance Policy \| Other Noncurrent Assets
Cash and Cash Equivalents
Restricted cash		$ 100,000
2013 Loan and Security Agreement \| Revolving Credit Facility
Cash and Cash Equivalents
Covenant terms, minimum required cash on deposit at lender	$ 7,500,000.0

Cash, Cash Equivalents and Short-Term Investments - Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents [Abstract]
Cash	$ 38,474	$ 58,289
Money market funds	20,010	0
Total cash and cash equivalents	$ 58,484	$ 58,289	$ 17,748	$ 5,961

Cash, Cash Equivalents and Short-Term Investments - Short-Term Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Short-Term Investments
Aggregate Fair Value	$ 0	$ 20,000
U.S. Treasury bills
Schedule of Short-Term Investments
Amortized Cost		20,000
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Aggregate Fair Value		$ 20,000

Financial Statement Components (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financial Statement Components [Abstract]
Depreciation and amortization of property and equipment	$ 6.9	$ 6.0	$ 4.3

Financial Statement Components - Schedule of Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounts Receivable
Allowance for doubtful accounts	$ (15)	$ (65)	$ (42)	$ (54)
Accounts receivable, net	10,567	8,335
Billed trade accounts receivable
Accounts Receivable
Trade accounts receivable	9,554	7,482
Unbilled trade accounts receivable, net of advance client deposits
Accounts Receivable
Trade accounts receivable	$ 1,028	$ 918

Financial Statement Components - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property and equipment	$ 35,703	$ 28,197
Accumulated depreciation and amortization	(22,478)	(15,626)
Property and equipment, net	13,225	12,571	$ 11,607
Computer and Network Equipment
Property, Plant and Equipment [Line Items]
Property and equipment	30,277	24,292
Computer Software
Property, Plant and Equipment [Line Items]
Property and equipment	3,566	2,264
Internal-use software development costs
Property, Plant and Equipment [Line Items]
Property and equipment	128	0
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Property and equipment	1,113	1,030
Leasehold Improvements
Property, Plant and Equipment [Line Items]
Property and equipment	$ 619	$ 611

Financial Statement Components - Schedule of Capital Leased Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financial Statement Components [Abstract]
Gross	$ 27,302	$ 21,025
Less: accumulated depreciation and amortization	(16,429)	(10,609)
Total	$ 10,873	$ 10,416

Financial Statement Components - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financial Statement Components [Abstract]
Accrued expenses	$ 2,193	$ 2,240
Accrued compensation and benefits	5,718	5,078
Accrued and other current liabilities	$ 7,911	$ 7,318

Goodwill and Intangible Assets (Details) - USD ($)	12 Months Ended
Goodwill and Intangible Assets (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment, accumulated	$ 0	$ 0
Amortization of Intangible Assets	500,000	500,000	$ 100,000
Impairment of intangible assets	$ 0	$ 0

Goodwill and Intangible Assets - Schedule of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	$ 3,170	$ 3,170
Accumulated Amortization	(1,129)	(617)
Total Net Carrying Amount	2,041	2,553
Developed Technology
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	2,460	2,460
Accumulated Amortization	(775)	(423)
Total Net Carrying Amount	1,685	2,037
Customer Relationships
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	520	520
Accumulated Amortization	(229)	(125)
Total Net Carrying Amount	291	395
Domain Names
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	50	50
Accumulated Amortization	(22)	(12)
Total Net Carrying Amount	28	38
Noncompete Agreements
Acquired Finite-Lived Intangible Assets
Gross Carrying Amount	140	140
Accumulated Amortization	(103)	(57)
Total Net Carrying Amount	$ 37	$ 83

Goodwill and Intangible Assets - Schedule of Expected Future Amortization Expense of Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2016	$ 503
2017	465
2018	442
2019	351
2020	280
Total Net Carrying Amount	$ 2,041	$ 2,553

Debt - 2013 Loan and Security Agreement (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Oct. 31, 2013
Debt Instrument [Line Items]
Debt, gross	$ 38,126,000
Notes Payable
Debt Instrument [Line Items]
Debt, gross	25,626,000	$ 27,140,000
Notes Payable \| 2013 Loan and Security Agreement
Debt Instrument [Line Items]
Debt, gross	2,500,000	$ 4,500,000
Revolving Credit Facility \| 2013 Loan and Security Agreement
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	20,000,000.0
Credit agreement, amount outstanding	12,500,000
Credit facility, remaining borrowing capacity	7,500,000
Covenant terms, minimum required cash on deposit at lender	$ 7,500,000.0
Revolving Credit Facility \| 2013 Loan and Security Agreement \| Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread (as a percentage)	0.50%
Term Loan \| 2013 Loan and Security Agreement
Debt Instrument [Line Items]
Amount borrowed under agreement			$ 5,000,000.0
Term Loan \| 2013 Loan and Security Agreement \| Prime Rate
Debt Instrument [Line Items]
Debt instrument, basis spread (as a percentage)	1.50%

Debt - 2014 Loan and Security Agreement (Details) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 28, 2014	Dec. 31, 2015	Nov. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total debt, net carrying value		$ 37,039,000		$ 38,424,000
Debt, gross		38,126,000
Term Loan \| 2014 Loan and Security Agreement
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	$ 30,000,000.0	30,000,000.0
Credit facility, remaining borrowing capacity		10,000,000.0
Credit facility, minimum incremental borrowing amount		1,000,000.0
Total debt, net carrying value		$ 20,000,000
Debt, gross				$ 20,000,000
Term Loan \| 2014 Loan and Security Agreement \| Prime Rate
Debt Instrument [Line Items]
Term loan, minimum interest rate		10.00%
Term Loan \| 2014 Loan and Security Agreement \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread (as a percentage)		9.00%
Term Loan \| Tranche One
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity	20,000,000
Payments of debt issuance costs	400,000
Debt, gross	$ 20,000,000
Common Stock \| Term Loan \| 2014 Loan and Security Agreement
Debt Instrument [Line Items]
Warrants issued	177,865
Exercise price (in dollars per share)	$ 10.12
Common Stock \| Term Loan \| Tranche One
Debt Instrument [Line Items]
Warrants vested, shares	118,577
Common Stock Warrant
Debt Instrument [Line Items]
Exercise price (in dollars per share)			$ 0.65
Common Stock Warrant \| Term Loan \| 2014 Loan and Security Agreement
Debt Instrument [Line Items]
Class of warrant or right, vesting period (in years)	10 years
Warrants unvested, shares		59,288

Debt - Promissory Note/FCC Civil Penalty (Details) $ in Thousands	1 Months Ended
	Jul. 31, 2013 USD ($) installment	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Jun. 12, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)
Debt Instrument [Line Items]
Debt, gross		$ 38,126
Discount on debt		1,087			$ 1,216
Total debt, net carrying value		37,039			38,424
FCC Enforcement Bureau Civil Penalty
Debt Instrument [Line Items]
Civil penalty				$ 2,000
Notes Payable
Debt Instrument [Line Items]
Debt, gross		25,626			27,140
Total debt, net carrying value		$ 24,539			25,924
Notes Payable \| Promissory Note
Debt Instrument [Line Items]
Promissory note issued	$ 4,100
Promissory note, stated interest rate	12.75%
Promissory note, number of monthly payments \| installment	42
Notes Payable \| FCC Enforcement Bureau Civil Penalty
Debt Instrument [Line Items]
Promissory note, stated interest rate		12.75%
Debt, gross		$ 1,667			0
Civil penalty		1,700	$ 2,000
Present value of civil penalty		1,700
Discount on debt			$ 300
Total debt, net carrying value		1,400
USF Obligations \| Promissory Note
Debt Instrument [Line Items]
Promissory note, carrying value					2,600
USF Obligations \| Notes Payable \| Promissory Note
Debt Instrument [Line Items]
Debt, gross		$ 1,500			$ 2,600
FCC Enforcement Bureau Civil Penalty
Debt Instrument [Line Items]
Accrued liability for civil penalty						$ 2,000

Debt - Schedule of Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Debt, gross	$ 38,126
Less: discount	(1,087)		$ (1,216)
Total debt, net carrying value	37,039		38,424
Less: current portion of debt	(19,712)		(3,146)
Total debt, less current portion	17,327		35,278
Notes Payable
Debt Instrument [Line Items]
Debt, gross	25,626		27,140
Total debt, net carrying value	24,539		25,924
Notes Payable \| 2014 Loan and Security Agreement
Debt Instrument [Line Items]
Debt, gross	20,000		20,000
Notes Payable \| 2013 Loan and Security Agreement
Debt Instrument [Line Items]
Debt, gross	2,500		4,500
Notes Payable \| Promissory Note to USAC
Debt Instrument [Line Items]
Debt, gross	1,459		2,640
Notes Payable \| FCC Civil Penalty
Debt Instrument [Line Items]
Debt, gross	1,667		0
Less: discount		$ (300)
Total debt, net carrying value	1,400
Line of Credit
Debt Instrument [Line Items]
Debt, gross	$ 12,500		$ 12,500

Debt - Schedule of Maturities of Debt (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Debt Disclosure [Abstract]
2016	$ 20,173
2017	5,286
2018	4,334
2019	8,333
Total	$ 38,126

Stockholders' Equity - Initial Public Offering (Details) - USD ($) $ / shares in Units, $ in Millions				6 Months Ended	21 Months Ended
	Apr. 22, 2014	Apr. 09, 2014	Dec. 31, 2013	Jun. 30, 2014	Jun. 30, 2014
Common Stock
Class of Stock [Line Items]
Offering price (in dollars per share)	$ 7.00
IPO
Class of Stock [Line Items]
Proceeds from IPO	$ 74.9
Underwriters discounts and commissions	$ 5.6
Offering expenses					$ 4.2
Payment of offering costs			$ 0.8	$ 3.4
IPO \| Common Stock
Class of Stock [Line Items]
Number of shares issued		10,000,000
Shares Issued To Underwriters Under Over Allotment Options	1,500,000
Offering price (in dollars per share)		$ 7.00

Stockholders' Equity - Capital Structure (Details)	Apr. 03, 2014 shares	Dec. 31, 2015 $ / shares shares	Dec. 31, 2014 $ / shares shares
Class of Stock [Line Items]
Preferred Stock, shares outstanding		0	0
Common Stock, shares authorized		450,000,000	450,000,000
Preferred Stock, shares authorized		5,000,000	5,000,000
Common Stock, par value \| $ / shares		$ 0.001	$ 0.001
Preferred Stock, par value \| $ / shares		$ 0.001	$ 0.001
Common Stock, shares issued		51,164,621	49,322,498
Common Stock, shares outstanding		51,164,621	49,322,498
Preferred Stock, shares issued		0	0
Series A-2 Convertible Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding	75,643,683
Series B-2 Convertible Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding	18,565,794
Series C-2 Convertible Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding	12,903,226
Series D-2 Convertible Preferred Stock
Class of Stock [Line Items]
Preferred Stock, shares outstanding	15,269,294
Convertible Preferred Stock
Class of Stock [Line Items]
Convertible preferred stock, conversion ratio	1
Convertible preferred stock, conversion ratio to common stock	30,595,477
IPO \| Common Stock
Class of Stock [Line Items]
Reverse stock split, conversion ratio	0.25

Stockholders' Equity - Common Stock Subject to Forfeiture (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Oct. 31, 2014	Oct. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Restricted Stock [Line Items]
Shares outstanding			51,164,621	49,322,498
Stock-based compensation expense			$ 7,730	$ 6,753	$ 1,949
Restricted Common Stock
Schedule of Restricted Stock [Line Items]
Shares outstanding			0
Restricted Common Stock \| Face It, Corp.
Schedule of Restricted Stock [Line Items]
Restricted common stock granted		118,577
Value per share (in dollars per share)		$ 8.48
Award vesting, percentage of award	50.00%
Restricted common stock outstanding (in shares)			59,289
Awards vested due to acceleration (in shares)			37,905
Unvested awards forfeited (in shares)			21,384
Stock-based compensation expense				$ 700	$ 200

Stockholders' Equity - Warrants Outstanding (Details) shares in Thousands	Dec. 31, 2015 $ / shares shares
Class of Warrant or Right [Line Items]
Warrants outstanding	191
October 2023
Class of Warrant or Right [Line Items]
Exercise price (in dollars per share) \| $ / shares	$ 5.76
Warrants outstanding	13
February 2024
Class of Warrant or Right [Line Items]
Exercise price (in dollars per share) \| $ / shares	$ 10.12
Warrants outstanding	178

Stockholders' Equity - Warrants Activity (Details) - $ / shares	1 Months Ended	12 Months Ended
	Nov. 30, 2015	Dec. 31, 2015
Shares
Outstanding, ending balance		191,000
Common Stock Warrant
Shares
Outstanding, beginning balance		360,000
Issued		0
Exercised	(168,711)	(169,000)
Outstanding, ending balance		191,000
Weighted Average Exercise Price
Outstanding, beginning balance, weighted-average exercise price		$ 5.59
Issued, weighted-average exercise price		0.00
Exercised, weighted-average exercise price		0.65
Outstanding, ending balance, weighted-average exercise price		$ 9.96
Exercise price (in dollars per share)	$ 0.65
Common Stock Warrant \| Common Stock
Weighted Average Exercise Price
Shares of common stock issued upon cashless exercise of warrants	151,905

Stockholders' Equity - Warrant Valuation Assumptions (Details) - $ / shares

12 Months Ended

Apr. 03, 2014

Dec. 31, 2013

IPO

Class of Stock [Line Items]

IPO price per share

$ 7.00

Warrants

Class of Stock [Line Items]

Expected dividends

0.00%

Volatility

45.00%

Warrants | Minimum [Member]

Class of Stock [Line Items]

Risk-free interest rate

0.13%

0.33%

Volatility

40.00%

Warrants | Maximum [Member]

Class of Stock [Line Items]

Risk-free interest rate

2.73%

2.60%

Volatility

50.00%

Warrants | Series A-2 Convertible Preferred Stock

Class of Stock [Line Items]

Fair value of stock

$ 1.75

^[1]

$ 2.69

^[2]

Warrants | Series D-2 Convertible Preferred Stock

Class of Stock [Line Items]

Fair value of stock

1.75

^[1]

$ 2.81

^[2]

Warrants | Common Stock

Class of Stock [Line Items]

Fair value of stock

^[1]

$ 7.00

[1]	Fair value of the underlying stock is based on the Company's IPO price of $7.00 per share calculated on a pre-reverse split basis for preferred stock and post-reverse split basis for common stock.
[2]	The per share data is on a pre-reverse split basis for preferred stock.

Stockholders' Equity - Common Stock Reserved for Future Issuance (Details) - shares	Dec. 31, 2015	Apr. 03, 2014
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	14,091,000
2014 Equity Incentive Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	5,079,000
Employee Stock Purchase Plan
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	911,106	880,000
Employee Stock Options
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	6,092,000
Restricted Stock Units
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	1,818,000
Warrants
Class of Stock [Line Items]
Shares of common stock reserved for future issuance	191,000

Stockholders' Equity - Equity Incentive Plans (Details) - shares	12 Months Ended
	Dec. 31, 2015	Jan. 01, 2016	Jan. 01, 2015
2004 Equity Incentive Plan \| Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	4 years
Award expiration period	10 years
Expiration period, after termination of employment or relationship of consultant or director	90 days
2004 Equity Incentive Plan \| Employee Stock Options \| Tranche One
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	12 months
Award vesting, percentage of award	25.00%
2004 Equity Incentive Plan \| Employee Stock Options \| Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	36 months
Award vesting, percentage of award	75.00%
2014 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award
Automatic annual increase in common stock reserved for issuance, percentage	5.00%
Shares of common stock reserved for future issuance, additional shares			2,466,124
2014 Equity Incentive Plan \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock reserved for future issuance, additional shares		2,558,231
2014 Equity Incentive Plan \| Employee Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Award expiration period	10 years
2014 Equity Incentive Plan \| Common Stock
Share-based Compensation Arrangement by Share-based Payment Award
Number of shares authorized for issuance	5,300,000
Shares available for future grant under the plan	5,079,164
2014 Equity Incentive Plan \| Restricted Stock Units \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	1 year
2014 Equity Incentive Plan \| Restricted Stock Units \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Award vesting period	4 years

Stockholders' Equity - Stock Option Activities (Details) - Employee Stock Options - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Number of Shares
Outstanding, beginning balance	7,164
Options granted	244
Options exercised	(840)
Options forfeited or expired	(476)
Outstanding, ending balance	6,092	7,164
Weighted Average Exercise Price
Outstanding, beginning balance, weighted-average exercise price	$ 4.34
Options granted, weighted-average exercise price	4.99
Options exercised, weighted-average exercise price	1.51
Options forfeited or expired, weighted-average exercise price	6.67
Outstanding, ending balance, weighted-average exercise price	$ 4.58	$ 4.34
Weighted average remaining contractual life	6 years 5 months 5 days
Outstanding, Aggregate intrinsic value	$ 27,243
Vested and expected to vest as of December 31, 2015
Vested and expected to vest, shares	5,998
Exercisable, shares	4,057
Outstanding, weighted-average exercise price	$ 4.54
Exercisable, weighted-average exercise price	$ 3.55
Outstanding, weighted average remaining contractual life	6 years 4 months 24 days
Exercisable, weighted average remaining contractual life	5 years 6 months 4 days
Vested and expected to vest, aggregate intrinsic value	$ 27,011
Exercisable, aggregate intrinsic value	$ 22,004
Fair market value of common stock	$ 8.70
Weighted-average grant date fair value per share of options granted	$ 2.38	$ 3.42	$ 4.19
Grant-date fair value of options vested	$ 4,824	$ 3,847	$ 1,417
Intrinsic value of options exercised	3,233	9,808	2,145
Proceeds from exercise of common stock options	$ 1,268	$ 1,127	$ 702

Stockholders' Equity - RSU Activities (Details) - Restricted Stock Units shares in Thousands	12 Months Ended
	Dec. 31, 2015 $ / shares shares
Number of Shares
Outstanding, beginning balance \| shares	1,370
RSUs granted \| shares	1,202
RSUs vested and released \| shares	(566)
RSUs forfeited \| shares	(188)
Outstanding, ending balance \| shares	1,818
Weighted Average Grant Date Fair Value Per Share
Outstanding, beginning balance, weighted-average grant date fair value per share \| $ / shares	$ 5.21
RSUs granted, weighted-average grant date fair value per share \| $ / shares	5.10
RSUs vested and released, weighted-average grant date fair value per share \| $ / shares	5.73
RSUs forfeited, weighted-average grant date fair value per share \| $ / shares	4.94
Outstanding, ending balance, weighted-average grant date fair value per share \| $ / shares	$ 5.01

Stockholders' Equity - ESPP (Details) - $ / shares	12 Months Ended
Stockholders' Equity - ESPP (Details) - $ / shares	Dec. 31, 2015	Jan. 01, 2016	Jan. 01, 2015	Apr. 03, 2014
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock reserved for future issuance	14,091,000
ESPP
Share-based Compensation Arrangement by Share-based Payment Award
Maximum employee subscription rate, percentage of pre-tax earnings	15.00%
Purchase price of shares, percentage of the fair market value of the Company's common stock	85.00%
Maximum number of shares per employee per purchase period	1,500
Shares of common stock reserved for future issuance	911,106			880,000
Shares of common stock reserved for future issuance, additional shares			493,224
Automatic annual increase in common stock reserved for issuance, percentage	1.00%
Maximum annual increase of shares reserved	1,000,000
Issuance of common stock under ESPP, shares	305,987
Weighted-average price per share	$ 4.47
ESPP \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award
Shares of common stock reserved for future issuance, additional shares		511,646

Stockholders' Equity - Stock-Based Compensation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based Compensation Expense
Stock-based compensation expense	$ 7,730	$ 6,753	$ 1,949
ESPP
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 202
Weighted-average amortization period	4 months 14 days
Employee Stock Options
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 6,983
Weighted-average amortization period	2 years 1 month 10 days
Restricted Stock Units
Stock-based Compensation Expense
Unrecognized stock-based compensation expense	$ 7,280
Weighted-average amortization period	3 years 15 days
Cost of Revenue
Stock-based Compensation Expense
Stock-based compensation expense	$ 866	542	194
Research and Development
Stock-based Compensation Expense
Stock-based compensation expense	1,790	1,931	499
Sales and Marketing
Stock-based Compensation Expense
Stock-based compensation expense	1,800	1,510	751
General and Administrative
Stock-based Compensation Expense
Stock-based compensation expense	$ 3,274	$ 2,770	$ 505

Stockholders' Equity - Option and ESPP Valuation Assumptions (Details)	1 Months Ended				12 Months Ended
	Nov. 30, 2015	May 31, 2015	Nov. 30, 2014	Apr. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ESPP
Class of Stock [Line Items]
Expected term (years)	6 months	6 months	6 months	9 months 24 days
Volatility	54.00%	43.00%	56.00%	39.00%
Risk-free interest rate	0.30%	0.10%	0.10%	0.10%
Dividend yield	0.00%	0.00%	0.00%	0.00%
Employee Stock Options
Class of Stock [Line Items]
Expected term (years)					6 years 29 days	6 years 28 days	6 years 10 days
Volatility					49.00%	55.00%	60.00%
Risk-free interest rate					1.60%	1.80%	1.50%
Dividend yield					0.00%	0.00%	0.00%

Net Loss Per Share - Basic and Diluted Net Loss Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1]

Jun. 30, 2014

^[2]

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Earnings Per Share [Abstract]

Net loss

$ (3,518)

$ (6,048)

$ (7,369)

$ (8,903)

$ (9,372)

$ (11,435)

$ (8,659)

$ (8,320)

$ (25,838)

$ (37,786)

$ (31,314)

Weighted-average shares used in computing basic and diluted net loss per share

50,764

50,369

49,980

49,433

49,003

48,310

46,898

5,608

50,141

37,604

4,006

Basic and diluted net loss per share

$ (0.07)

$ (0.12)

$ (0.15)

$ (0.18)

$ (0.19)

$ (0.24)

$ (0.18)

$ (1.48)

$ (0.52)

$ (1.00)

$ (7.82)

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Net Loss Per Share - Antidilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	8,257	9,145	38,712
Convertible Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	0	0	30,554
Employee Stock Options
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	6,092	7,164	7,633
Restricted Stock Units
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	1,818	1,370	0
ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	156	192	0
Warrants \| Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	191	360	0
Warrants \| Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	0	0	391
Common stock subject to repurchase or forfeiture
Antidilutive Securities Excluded from Computation of Earnings Per Share
Anti-dilutive securities excluded from calculation of diluted net loss per share	0	59	134

Income Taxes (Details) - USD ($) $ in Millions	12 Months Ended
Income Taxes (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Loss Carryforwards [Line Items]
U.S. federal income tax rate (percent)	34.00%	34.00%	34.00%
Undistributed earnings of foreign subsidiaries	$ 0.8
Limitation on use of net operating loss, cumulative ownership change, more than	50.00%
Limitation on use of net operating loss, cumulative ownership change, period of change	3 years
Federal
Operating Loss Carryforwards [Line Items]
Increase in valuation allowance for deferred tax assets	$ 8.4	$ 13.4
Net operating loss carryforwards	$ 124.4
Net operating loss carryforwards, expiration date	Jan. 01, 2024
Federal \| Research and Development Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards	$ 2.2
Research and development credit carryforwards, expiration date	Jan. 01, 2022
State
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 85.2
Net operating loss carryforwards, expiration date	Jan. 01, 2015
State \| Research and Development Tax Credit Carryforward
Operating Loss Carryforwards [Line Items]
Research and development credit carryforwards	$ 1.8

Income Taxes - Schedule of Components of Loss before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
United States	$ (26,305)	$ (37,657)	$ (31,628)
International	528	(44)	384
Loss before income taxes	$ (25,777)	$ (37,701)	$ (31,244)

Income Taxes - Schedule of Components of Provision for Income Taxes (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1]

Jun. 30, 2014

^[2]

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Income Tax Disclosure [Abstract]

U.S. federal

$ 0

U.S. state

Foreign

Total provision for income taxes

$ 13

$ 50

$ (20)

$ 18

$ 33

$ 13

$ 12

$ 27

$ 61

$ 85

$ 70

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

Income Taxes - Schedule of Effective Income Tax Amount Reconciliation (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1]

Jun. 30, 2014

^[2]

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Income Tax Disclosure [Abstract]

U.S. federal tax at statutory rate

$ (8,764)

$ (12,818)

$ (10,623)

U.S. state income taxes

(756)

(1,098)

(786)

Non-deductible expenses

438

420

1,383

Research and development credit

(440)

(455)

(339)

Stock-based compensation

737

746

444

Other

481

(72)

(586)

Change in valuation allowance

8,365

13,362

10,577

Total provision for income taxes

$ 13

$ 50

$ (20)

$ 18

$ 33

$ 13

$ 12

$ 27

$ 61

$ 85

$ 70

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss and credit carryforwards	$ 45,671	$ 39,211
Accrued liabilities	5,488	4,308
Allowance for doubtful accounts	394	256
Accrued compensation	817	626
Intangibles	23	23
Gross deferred tax assets	52,393	44,424
Valuation allowance	(51,568)	(43,203)
Net deferred tax assets	825	1,221
Deferred tax liabilities:
Property and equipment	(71)	(278)
Amortized intangibles	(754)	(943)
Gross deferred tax liabilities	(825)	(1,221)
Net deferred taxes	$ 0	$ 0

Income Taxes - Schedule of Unrecognized Tax Benefits Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits
Unrecognized benefit — beginning of period	$ 1,975	$ 1,455	$ 1,075
Gross increases — current year tax positions	522	532	382
Gross decreases — prior year tax positions	(12)	(12)	(2)
Unrecognized benefit — end of period	$ 2,485	$ 1,975	$ 1,455

Commitments and Contingencies - Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capital Leases
2016	$ 6,079
2017	4,289
2018	779
2019	37
Total future minimum lease payment	11,184
Less — amount representing interest	(1,606)
Present value of total capital lease obligation	9,578
Capital lease obligation — current portion	4,972	$ 4,849
Capital lease obligation — net of current portion	4,606	4,423
Operating Leases
Rent expense	2,000	$ 2,600	$ 2,300
2016	2,144
2017	1,879
2018	304
2019	0
Total future minimum lease payment	$ 4,327

Commitments and Contingencies - Hosting, Telecommunications Usuage and Maintenance Services (Details) $ in Thousands	Dec. 31, 2015 USD ($)
Hosting Services
Unrecorded Unconditional Purchase Obligation [Line Items]
2016	$ 1,573
2017	832
2018	10
Total future minimum payment	2,415
Telecommunication Usage Services
Unrecorded Unconditional Purchase Obligation [Line Items]
2016	765
2017	1,036
2018	4
Total future minimum payment	1,805
Equipment Maintenance Services
Unrecorded Unconditional Purchase Obligation [Line Items]
2016	332
2017	177
2018	0
Total future minimum payment	$ 509

Commitments and Contingencies - Universal Services Fund Liability (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2015	Jun. 12, 2015	Sep. 30, 2014	Dec. 31, 2012
Loss Contingencies [Line Items]
Accrued federal fees		$ 5,684	$ 7,215
Promissory note payable		38,126
FCC Enforcement Bureau Civil Penalty
Loss Contingencies [Line Items]
Accrued liability for civil penalty							$ 2,000
General and Administrative
Loss Contingencies [Line Items]
interest and penalty expense		500	500	$ 200
Periods Prior To 2008 \| USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees			800
2003 through 2012 \| USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees								$ 8,100
Undisputed portion [Member] \| 2003 through 2012 \| USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees								4,700
Payments for state and local taxes on usage-based fees	$ 600
Disputed portion [Member] \| 2003 through 2012 \| USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees		4,900	4,200					3,400
Disputed portion [Member] \| 2003 through 2007 \| USF Obligations
Loss Contingencies [Line Items]
Accrued federal fees								$ 800
Promissory Note to USAC \| USF Obligations
Loss Contingencies [Line Items]
Promissory note issued	4,100
FCC Enforcement Bureau Civil Penalty
Loss Contingencies [Line Items]
Civil penalty						$ 2,000
Notes Payable
Loss Contingencies [Line Items]
Promissory note payable		25,626	27,140
Notes Payable \| Promissory Note to USAC
Loss Contingencies [Line Items]
Promissory note payable		1,459	2,640
Notes Payable \| FCC Enforcement Bureau Civil Penalty
Loss Contingencies [Line Items]
Promissory note payable		1,667	0
Civil penalty		1,700			$ 2,000
Notes Payable \| Promissory Note
Loss Contingencies [Line Items]
Promissory note issued	$ 4,100
Notes Payable \| Promissory Note \| USF Obligations
Loss Contingencies [Line Items]
Promissory note payable		$ 1,500	$ 2,600

Commitments and Contingencies - State and Local Taxes and Surcharges (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

May 31, 2014

Dec. 31, 2015

Sep. 30, 2015

^[1],[2]

Jun. 30, 2015

^[1],[2]

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1],[2],[3]

Jun. 30, 2014

^[1],[2],[4]

Mar. 31, 2014

^[1],[2]

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Loss Contingencies [Line Items]

General and administrative expense

$ 6,433

^[1],[2]

$ 6,087

$ 6,027

$ 7,275

^[1],[2]

$ 6,763

^[1],[2]

$ 7,967

$ 3,515

$ 6,171

$ 25,822

$ 24,416

$ 18,053

Sales tax liability, current

1,262

297

1,262

297

Sales tax liability — less current portion

1,915

2,582

1,915

2,582

Contingent sales tax liabilities

Loss Contingencies [Line Items]

General and administrative expense

1,200

1,100

$ 2,200

Payments for state and local taxes on usage-based fees

1,100

Sales tax liability, current

800

Sales tax liability — less current portion

1,900

Potential Obligation for State Taxes on Usage Based Fees

Loss Contingencies [Line Items]

Sales tax liability — less current portion

$ 2,700

$ 2,600

$ 2,700

$ 2,600

Out of Period Adjustment | Contingent sales tax liabilities

Loss Contingencies [Line Items]

General and administrative expense

$ 600

Period 2011 to Q1 2014 | Reversal of sales tax liability | Potential Obligation for State Taxes on Usage Based Fees

Loss Contingencies [Line Items]

Reversal of sales tax liability

$ (2,800)

Period 2011 to 2013 | Reversal of sales tax liability | Potential Obligation for State Taxes on Usage Based Fees

Loss Contingencies [Line Items]

Reversal of sales tax liability

$ (2,500)

[1]	Included depreciation and amortization expenses as follows: Quarter Ended Dec. 31,2015 Sept. 30,2015 Jun. 30,2015 Mar. 31,2015 Dec. 31,2014 Sept. 30,2014 Jun. 30,2014 Mar. 31,2014 (unaudited, in thousands)Cost of revenue $1,483 $1,470 $1,558 $1,439 $1,291 $1,272 $1,373 $1,202Research and development 140 126 102 87 75 58 50 46Sales and marketing 54 52 51 49 50 50 48 48General and administrative 186 192 199 200 189 187 228 296Total depreciation and amortization $1,863 $1,840 $1,910 $1,775 $1,605 $1,567 $1,699 $1,592
[2]	Included stock-based compensation as follows: Quarter Ended Dec. 31,2015 Sept. 30,2015 Jun. 30,2015 Mar. 31,2015 Dec. 31,2014 Sept. 30,2014 Jun. 30,2014 Mar. 31,2014 (unaudited, in thousands)Cost of revenue $227 $233 $218 $188 $176 $158 $121 $87Research and development 401 475 340 574 527 583 471 350Sales and marketing 370 448 458 524 455 361 368 326General and administrative 722 789 814 949 799 775 763 433Total stock-based compensation $1,720 $1,945 $1,830 $2,235 $1,957 $1,877 $1,723 $1,196
[3]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[4]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

Geographical Information - Schedule of Revenue and Property and Equipment by Geographic Region (Details) - USD ($)
$ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

^[1]

Jun. 30, 2014

^[2]

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Revenues from External Customers and Long-Lived Assets

Revenue

$ 36,033

$ 32,287

$ 30,274

$ 28,274

$ 25,869

$ 24,685

$ 24,274

$ 128,868

$ 103,102

$ 84,132

Property and equipment, net

13,225

12,571

13,225

12,571

11,607

United States

Revenues from External Customers and Long-Lived Assets

Revenue

120,037

95,345

75,374

Property and equipment, net

10,939

10,625

10,939

10,625

11,079

International

Revenues from External Customers and Long-Lived Assets

Revenue

8,831

7,757

8,758

Property and equipment, net

$ 2,286

$ 1,946

$ 2,286

$ 1,946

$ 528

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.

Selected Quarterly Financial Data (Unaudited) - Schedule of Quarterly Financial Information (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands

3 Months Ended

12 Months Ended

Dec. 31, 2015

Sep. 30, 2015

Jun. 30, 2015

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Revenue

$ 36,033

$ 32,287

$ 30,274

$ 28,274

$ 25,869

^[1]

$ 24,685

^[2]

$ 24,274

$ 128,868

$ 103,102

$ 84,132

Cost of revenue

15,635

^[3],[4]

14,812

^[3],[4]

14,270

^[3],[4]

14,778

^[3],[4]

14,540

^[3],[4]

13,504

^[1],[3],[4]

13,469

^[2],[3],[4]

13,148

^[3],[4]

59,495

54,661

48,807

Gross profit

20,398

17,475

16,004

15,496

13,734

12,365

^[1]

11,216

^[2]

11,126

69,373

48,441

35,325

Operating expenses:

Research and development

5,580

^[3],[4]

5,473

^[3],[4]

5,568

^[3],[4]

6,038

^[3],[4]

5,828

^[3],[4]

5,503

^[1],[3],[4]

5,554

^[2],[3],[4]

5,225

^[3],[4]

22,659

22,110

17,529

Sales and marketing

10,720

^[3],[4]

10,797

^[3],[4]

10,594

^[3],[4]

9,931

^[3],[4]

9,453

^[3],[4]

9,296

^[1],[3],[4]

9,674

^[2],[3],[4]

9,022

^[3],[4]

42,042

37,445

28,065

General and administrative

6,433

^[3],[4]

6,087

^[3],[4]

6,027

^[3],[4]

7,275

^[3],[4]

6,763

^[3],[4]

7,967

^[1],[3],[4]

3,515

^[2],[3],[4]

6,171

^[3],[4]

25,822

24,416

18,053

Total operating expenses

22,733

22,357

22,189

23,244

22,044

22,766

^[1]

18,743

^[2]

20,418

90,523

83,971

63,647

Loss from operations

(2,335)

(4,882)

(6,185)

(7,748)

(8,310)

(10,401)

^[1]

(7,527)

^[2]

(9,292)

(21,150)

(35,530)

(28,322)

Other income (expense), net:

Interest expense

(1,198)

(1,235)

(1,155)

(1,139)

(1,175)

(1,116)

^[1]

(1,092)

^[2]

(778)

(4,727)

(4,161)

(1,080)

Interest income and other

119

(49)

146

^[1]

(28)

^[2]

100

245

Change in fair value of convertible preferred and common stock warrant liabilities

^[1]

^[2]

1,745

(1,871)

Total other income (expense), net

(1,170)

(1,116)

(1,204)

(1,137)

(1,029)

(1,021)

^[1]

(1,120)

^[2]

999

(4,627)

(2,171)

(2,922)

Loss before income taxes

(3,505)

(5,998)

(7,389)

(8,885)

(9,339)

(11,422)

^[1]

(8,647)

^[2]

(8,293)

(25,777)

(37,701)

(31,244)

Provision for (benefit from) income taxes

(20)

^[1]

^[2]

Net loss

$ (3,518)

$ (6,048)

$ (7,369)

$ (8,903)

$ (9,372)

$ (11,435)

^[1]

$ (8,659)

^[2]

$ (8,320)

$ (25,838)

$ (37,786)

$ (31,314)

Net loss per share:

Basic and diluted (in USD per share)

$ (0.07)

$ (0.12)

$ (0.15)

$ (0.18)

$ (0.19)

$ (0.24)

^[1]

$ (0.18)

^[2]

$ (1.48)

$ (0.52)

$ (1.00)

$ (7.82)

Shares used in computing net loss per share:

Basic and diluted (in shares)

50,764

50,369

49,980

49,433

49,003

48,310

^[1]

46,898

^[2]

5,608

50,141

37,604

4,006

General and Administrative

Shares used in computing net loss per share:

Amount resulting from favorable ruling from specific state's revenue authority

$ 2,800

General and Administrative | USF Obligations

Shares used in computing net loss per share:

Expected settlement

$ 2,000

[1]	General and administrative for the third quarter of 2014 included a $2.0 million charge for an expected settlement with the FCC Enforcement Bureau. See Note 11.
[2]	General and administrative for the second quarter of 2014 included a $2.8 million credit recorded as a result of a favorable ruling from a specific state's revenue authority. See Note 11.
[3]	Included depreciation and amortization expenses as follows: Quarter Ended Dec. 31,2015 Sept. 30,2015 Jun. 30,2015 Mar. 31,2015 Dec. 31,2014 Sept. 30,2014 Jun. 30,2014 Mar. 31,2014 (unaudited, in thousands)Cost of revenue $1,483 $1,470 $1,558 $1,439 $1,291 $1,272 $1,373 $1,202Research and development 140 126 102 87 75 58 50 46Sales and marketing 54 52 51 49 50 50 48 48General and administrative 186 192 199 200 189 187 228 296Total depreciation and amortization $1,863 $1,840 $1,910 $1,775 $1,605 $1,567 $1,699 $1,592
[4]	Included stock-based compensation as follows: Quarter Ended Dec. 31,2015 Sept. 30,2015 Jun. 30,2015 Mar. 31,2015 Dec. 31,2014 Sept. 30,2014 Jun. 30,2014 Mar. 31,2014 (unaudited, in thousands)Cost of revenue $227 $233 $218 $188 $176 $158 $121 $87Research and development 401 475 340 574 527 583 471 350Sales and marketing 370 448 458 524 455 361 368 326General and administrative 722 789 814 949 799 775 763 433Total stock-based compensation $1,720 $1,945 $1,830 $2,235 $1,957 $1,877 $1,723 $1,196

Selected Quarterly Financial Date (Unaudited) - Allocation of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Total stock-based compensation	$ 1,720	$ 1,945	$ 1,830	$ 2,235	$ 1,957	$ 1,877	$ 1,723	$ 1,196	$ 7,730	$ 6,753	$ 1,949
Cost of Revenue
Total stock-based compensation	227	233	218	188	176	158	121	87
Research and Development
Total stock-based compensation	401	475	340	574	527	583	471	350
Sales and Marketing
Total stock-based compensation	370	448	458	524	455	361	368	326
General and Administrative
Total stock-based compensation	$ 722	$ 789	$ 814	$ 949	$ 799	$ 775	$ 763	$ 433

Selected Quarterly Financial Data (Unaudited) - Allocation of Depreciation and Amortization Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Total depreciation and amortization	$ 1,863	$ 1,840	$ 1,910	$ 1,775	$ 1,605	$ 1,567	$ 1,699	$ 1,592	$ 7,388	$ 6,463	$ 4,415
Cost of Revenue
Total depreciation and amortization	1,483	1,470	1,558	1,439	1,291	1,272	1,373	1,202
Research and Development
Total depreciation and amortization	140	126	102	87	75	58	50	46
Sales and Marketing
Total depreciation and amortization	54	52	51	49	50	50	48	48
General and Administrative
Total depreciation and amortization	$ 186	$ 192	$ 199	$ 200	$ 189	$ 187	$ 228	$ 296