Stockholders Equity and Redeemable Noncontrolling Interests (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Increase (Decrease) in Shareholders' Equity
Balance	$ 113,176,000
Issuance of common stock upon exercise and early exercise of stock options	965,000
Issuance of common stock under employee stock purchase plan	2,885,000
Investment by redeemable non-controlling interests	233,000
Vesting of early exercised options	42,000	115,000
Stock-based compensation expense	9,795,000
Net loss	(18,158,000)	(12,509,000)
Foreign currency translation adjustments	86,000
Balance	109,024,000
Redeemable Non-controlling Interests
Balance	800,000
Investment by redeemable non-controlling interests	1,445,000
Net loss attributable to redeemable noncontrolling interests	(454,000)	(11,000)
Foreign currency translation adjustments	3,000
Balance	1,794,000
Capitalized stock-based compensation associated with internal-use software projects	$ 500,000