Consolidated Statements of Convertible Preferred Stock and Stockholders' (Deficit) Equity - USD ($) shares in Thousands, $ in Thousands	Total	Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance at Dec. 31, 2012	$ (72,706)	$ 105,710	$ 5	$ 4,638	$ (77,349)	$ 0
Beginning Balance, shares at Dec. 31, 2012		18,753	4,658
Issuance of stock, net of issuance costs	109,307	$ 0	$ 8	109,299	0	0
Issuance of stock, shares		0	8,625
Conversion of warrant to purchase convertible preferred stock into warrant to purchase common stock	745	$ 0	$ 0	745	0	0
Conversion of warrant to purchase convertible preferred stock into warrant to purchase common stock, shares		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	$ 1,649	$ 0	$ 1	1,648	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	618	0	725
Issuance of common stock from cashless exercise of warrants	$ 0	$ 0	$ 0	0	0	0
Issuance of common stock from cashless exercise of warrants, shares		0	68
Issuance of common stock under employee stock purchase plan	1,231	$ 0	$ 0	1,231	0	0
Issuance of common stock under employee stock purchase plan, shares		0	146
Stock-based compensation expense	5,218	$ 0	$ 0	5,218	0	0
Repurchase of unvested shares	(77)	$ 0	$ 0	(77)	0	0
Repurchase of unvested shares, shares		0	(22)
Stock-based compensation tax benefits	119	$ 0	$ 0	119	0	0
Net loss	(35,852)	0	0	0	(35,852)	0
Ending Balance at Dec. 31, 2013	115,344	$ 0	$ 33	228,512	(113,201)	0
Ending Balance, shares at Dec. 31, 2013		0	32,953
Conversion of convertible preferred stock into common stock	105,710	$ (105,710)	$ 19	105,691	0	0
Conversion of convertible preferred stock into common stock, shares		(18,753)	18,753
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	$ 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	0	938
Issuance of common stock under employee stock purchase plan	$ 1,402	$ 0	$ 0	1,402	0	0
Issuance of common stock under employee stock purchase plan, shares		0	178
Issuance of unrestricted common stock in connection with acquisition	11,195	$ 0	$ 2	11,193	0	0
Issuance of unrestricted common stock in connection with acquisition, shares		0	1,119
Transaction costs incurred in connection with acquisition	(52)	$ 0	$ 0	(52)	0	0
Stock-based compensation expense	9,242	0	0	9,242	0	0
Repurchase of unvested shares	(20)	$ 0	$ 0	(20)	0	0
Repurchase of unvested shares, shares		0	(7)
Stock-based compensation tax benefits	126	$ 0	$ 0	126	0	0
Net loss	(33,171)	0	0	0	(33,171)	0
Ending Balance at Dec. 31, 2014	106,117	$ 0	$ 35	253,221	(146,392)	(747)
Ending Balance, shares at Dec. 31, 2014		0	35,181
Foreign currency translation adjustments and other, net	(790)	$ 0	$ 0	(23)	(20)	(747)
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	$ 0	$ 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	0	1,345
Tax withholding related to vesting of restricted stock units	$ (571)	$ 0	$ 0	(571)	0	0
Issuance of common stock under employee stock purchase plan	1,035	$ 0	$ 0	1,035	0	0
Issuance of common stock under employee stock purchase plan, shares		0	257
Issuance of unrestricted common stock in connection with acquisition	4,338	$ 0	$ 1	4,337	0	0
Issuance of unrestricted common stock in connection with acquisition, shares		0	636
Transaction costs incurred in connection with acquisition	(51)	$ 0	$ 0	(51)	0	0
Stock-based compensation expense	15,619	0	0	15,619	0	0
Repurchase of unvested shares	(2)	$ 0	$ 0	(2)	0	0
Repurchase of unvested shares, shares		0	0
Stock-based compensation tax benefits	3	$ 0	$ 0	3	0	0
Net loss	(33,349)	0	0	0	(33,349)	0
Ending Balance at Dec. 31, 2015	94,131	$ 0	$ 37	275,604	(179,733)	(1,777)
Ending Balance, shares at Dec. 31, 2015		0	37,419
Foreign currency translation adjustments and other, net	$ (1,022)	$ 0	$ 0	$ 0	$ 8	$ (1,030)