Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2013	$ 115,344	$ 33	$ 228,512	$ (113,201)	$ 0
Beginning Balance, shares at Dec. 31, 2013		32,953
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase	$ 2,841	$ 0	2,841	0	0
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase, shares	791	938
Issuance of common stock under employee stock purchase plan	$ 1,402	$ 0	1,402	0	0
Issuance of common stock under employee stock purchase plan, shares		178
Issuance of unrestricted common stock in connection with acquisition	11,195	$ 2	11,193	0	0
Issuance of unrestricted common stock in connection with acquisition, shares		1,119
Stock issuance costs incurred in connection with acquisition	(52)	$ 0	(52)	0	0
Stock-based compensation expense	9,242	0	9,242	0	0
Repurchase of unvested shares	(20)	$ 0	(20)	0	0
Repurchase of unvested shares, shares		(7)
Stock-based compensation tax benefits	126	$ 0	126	0	0
Net loss	(33,171)	0	0	(33,171)	0
Foreign currency translation adjustments and other, net	(790)	0	(23)	(20)	(747)
Ending Balance at Dec. 31, 2014	106,117	$ 35	253,221	(146,392)	(747)
Ending Balance, shares at Dec. 31, 2014		35,181
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase	$ 2,014	$ 1	2,013	0	0
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase, shares	727	1,345
Tax withholding related to vesting of restricted stock units	$ (571)	$ 0	(571)	0	0
Issuance of common stock under employee stock purchase plan	1,035	$ 0	1,035	0	0
Issuance of common stock under employee stock purchase plan, shares		257
Issuance of unrestricted common stock in connection with acquisition	4,338	$ 1	4,337	0	0
Issuance of unrestricted common stock in connection with acquisition, shares		636
Stock issuance costs incurred in connection with acquisition	(51)	$ 0	(51)	0	0
Stock-based compensation expense	15,619	0	15,619	0	0
Repurchase of unvested shares	(2)	$ 0	(2)	0	0
Repurchase of unvested shares, shares		0
Stock-based compensation tax benefits	3	$ 0	3	0	0
Net loss	(33,349)	0	0	(33,349)	0
Foreign currency translation adjustments and other, net	(1,022)	0	0	8	(1,030)
Ending Balance at Dec. 31, 2015	94,131	$ 37	275,604	(179,733)	(1,777)
Ending Balance, shares at Dec. 31, 2015		37,419
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase	$ 570	$ 1	569	0	0
Issuance of common stock from exercise of vested stock options, vesting of restricted stock units and vesting of options and shares subject to repurchase, shares	264	612
Tax withholding related to vesting of restricted stock units	$ (362)	$ 0	(362)	0	0
Issuance of common stock under employee stock purchase plan	547	$ 0	547	0	0
Issuance of common stock under employee stock purchase plan, shares		292
Issuance of unrestricted common stock in connection with acquisition	1	$ 1	0	0	0
Issuance of unrestricted common stock in connection with acquisition, shares		464
Stock-based compensation expense	10,295	$ 0	10,295	0	0
Net loss	(16,480)	0	0	(16,480)	0
Foreign currency translation adjustments and other, net	(1,104)	0	6	0	(1,110)
Ending Balance at Dec. 31, 2016	$ 87,598	$ 39	$ 286,659	$ (196,213)	$ (2,887)
Ending Balance, shares at Dec. 31, 2016		38,787