Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Accumulated Deficit [Member]
Balance at Dec. 31, 2012	$ 72,580	$ 39	$ 186,287	$ 8	$ (113,754)
Balance, shares at Dec. 31, 2012		35,852,105
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	$ 2,647	$ 2	2,645
Issuance of common stock upon exercise of stock options, shares	791,198	791,198
Issuance of common stock in connection with ESPP	$ 791		791
Issuance of common stock in connection with ESPP, shares		188,467
Proceeds for repayment of notes receivable from a stockholder	0
Issuance of common stock upon vesting of RSUs	0
Issuance of common stock upon vesting of RSUs, shares		292,265
Tax payments related to shares withheld for vested restricted stock units	$ (876)		(876)
Common stock traded for employee tax obligation (shares)	(85,661)	(85,661)
Stock-based compensation	$ 6,660		6,660
Change in unrealized gain (loss) on marketable securities, net of tax	2			2
Currency translation adjustments, net of tax	77			77
Net income (loss)	(19,305)				(19,305)
Balance at Dec. 31, 2013	62,576	$ 41	195,507	87	(133,059)
Balance, shares at Dec. 31, 2013		37,038,374
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	$ 2,787	$ 1	2,786
Issuance of common stock upon exercise of stock options, shares	569,283	569,283
Issuance of common stock in connection with ESPP	$ 1,532		1,532
Issuance of common stock in connection with ESPP, shares		103,089
Issuance of common stock upon vesting of RSUs	0
Issuance of common stock upon vesting of RSUs, shares		724,400
Tax payments related to shares withheld for vested restricted stock units	$ (6,594)		(6,594)
Common stock traded for employee tax obligation (shares)	(311,368)	(311,148)
Stock-based compensation	$ 9,383		9,383
Tax benefit from employee stock plans			87
Change in unrealized gain (loss) on marketable securities, net of tax	(16)			(16)
Currency translation adjustments, net of tax	(767)			(767)
Net income (loss)	1,531				1,531
Balance at Dec. 31, 2014	70,519	$ 42	202,701	(696)	(131,528)
Balance, shares at Dec. 31, 2014		38,123,998
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options	$ 4,136	$ 1	4,135
Issuance of common stock upon exercise of stock options, shares	608,931	608,931
Issuance of common stock in connection with ESPP	$ 2,492		2,492
Issuance of common stock in connection with ESPP, shares		108,552
Issuance of common stock upon vesting of RSUs	0
Issuance of common stock upon vesting of RSUs, shares		635,256
Tax payments related to shares withheld for vested restricted stock units	$ (8,283)		(8,283)
Common stock traded for employee tax obligation (shares)	(259,107)	(259,107)
Stock-based compensation	$ 13,219		13,219
Tax benefit from employee stock plans	1,357		1,357
Change in unrealized gain (loss) on marketable securities, net of tax	(15)			(15)
Currency translation adjustments, net of tax	(925)			(925)
Net income (loss)	41,802				41,802
Balance at Dec. 31, 2015	$ 124,302	$ 43	$ 215,621	$ (1,636)	$ (89,726)
Balance, shares at Dec. 31, 2015		39,217,630