Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2014

Summary of Significant Accounting Policies [Abstract]

Cash and cash equivalents as of December 31, 2014 consist of the following:


	December 31, 2014
Description	Contracted Maturity		Amortized Cost		Fair Market Value				Balance Per Balance Sheet
Cash		Demand	$	13,342	$	13,342	$	13,342
Money market funds		Demand		9,574		9,574		9,574
Total cash and cash equivalents			$	22,916	$	22,916	$	22,916

Cash, cash equivalents and investments as of December 31, 2013 consist of the following:


	December 31, 2013
Description	Contracted Maturity		Amortized Cost		Fair Market Value			Balance Per Balance Sheet
Cash		Demand	$	19,250	$	19,250	$	19,250
Money market funds		Demand		13,797		13,797		13,797
Total cash and cash equivalents			$	33,047	$	33,047	$	33,047
Certificates of deposit		110 - 163 days	$	960	$	961	$	960
Corporate debentures		23 - 96 days		2,101		2,102		2,101
Total short-term investments			$	3,061	$	3,063	$	3,061

Summary of Changes in Company's Allowance for Doubtful Accounts

Below is a summary of the changes in the Company's allowance for doubtful accounts for the years ended December 31, 2014, 2013 and 2012:


	Balance at Beginning of Period		Provision		Write-offs			Balance at End of Period
Year ended December 31, 2014	$	461	$	118	$	(398	)	$	181
Year ended December 31, 2013		338		449		(326	)		461
Year ended December 31, 2012		266		137		(65	)		338

Property and Equipment

Property and equipment consists of the following:


	Estimated Useful Life (in Years)		December 31,
	Estimated Useful Life (in Years)		2014		2013
Computer equipment		3	$	19,815	$	14,275
Software		3 - 6		9,245		8,473
Furniture and fixtures		5		1,827		1,721
Leasehold improvements		Shorter of lease term or the estimated useful life		929		737
				31,816		25,206
Less accumulated depreciation and amortization				21,444		16,411
			$	10,372	$	8,795

Reconciliation of Number of Shares Used in Calculation of Basic and Diluted Net Loss Per Share

A reconciliation of the number of shares used in the calculation of basic and diluted net loss per share is as follows:


	Year Ended December 31,
	2014			2013			2012
	(in thousands, except per share data)
Computation of basic and diluted net loss per share:
Net loss attributable to common stockholders	$	(16,893	)	$	(10,262	)	$	(13,919	)
Weighted-average shares of common stock outstanding		31,949			28,351			24,662
Less: weighted-average number of unvested restricted common shares outstanding		—			—			36
Weighted-average number of common shares used in calculating net loss per common share		31,949			28,351			24,626
Net loss per share applicable to common stockholders	$	(0.53	)	$	(0.36	)	$	(0.57	)

Potentially Dilutive Common Shares Excluded from Computation of Weighted-Average Shares Outstanding

The following potentially dilutive common shares have been excluded from the computation of weighted-average shares outstanding as of December 31, 2014, 2013 and 2012, as their effect would have been antidilutive:


	Year Ended December 31,
	2014		2013		2012
	(in thousands)
Redeemable convertible preferred stock		—		—		2,162
Options outstanding		3,805		3,331		3,894
Restricted stock units outstanding		990		1,398		384
Unvested restricted shares		—		—		36
Warrants		28		28		34

Weighted Average Assumptions Utilized

The weighted-average assumptions utilized to determine such values are presented in the following table:


	Year Ended December 31,
	2014			2013			2012
Risk-free interest rate		2.16	%		1.80	%		1.25	%
Expected volatility		52	%		54	%		57	%
Expected life (in years)		6.2			6.2			6.2
Expected dividend yield		—			—			—