Stockholders' Equity and Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Increase (Decrease) in Shareholders' Equity
Balance			$ 113,176
Issuance of common stock upon exercise and early exercise of stock options			4,765
Issuance of common stock under employee stock purchase plan			5,629
Investment by redeemable non-controlling interests			233
Adjustment to redemption value	$ (1,630)		(2,542)
Withholding taxes for the net share settlement of an equity award			(405)
Vesting of early exercised options			111	$ 236
Stock-based compensation expense			30,532
Net loss before adjustment to redemption value			(51,804)
Foreign currency translation adjustments attributable to parent			(40)
Balance	99,655		99,655
Redeemable Non-controlling Interests
Balance			800
Investment by redeemable non-controlling interests			1,445
Adjustment to redemption value, non-controlling interests			2,542
Net income loss attributable to redeemable non-controlling interest before adjustment	(367)	$ (206)	(1,236)	(376)
Foreign currency translation adjustments attributable to non-controlling interests			(10)
Balance	3,541		3,541
Stock-based compensation expense	$ 10,667	$ 6,515	29,674	$ 17,433
Capitalized stock-based compensation associated with internal-use software projects			$ 900