Stockholders Equity and Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Jun. 30, 2014
Increase (Decrease) in Shareholders' Equity
Balance		$ 113,176
Issuance of common stock upon exercise and early exercise of stock options		3,018
Issuance of common stock under employee stock purchase plan		2,885
Investment by redeemable non-controlling interests		233
Adjustment to redemption value	$ (912)	(912)
Withholding taxes for the net share settlement of an equity award		(77)
Vesting of early exercised options		82	$ 190
Stock-based compensation expense		19,723
Net loss before adjustment to redemption value		(35,196)
Foreign currency translation adjustments		(32)
Balance	102,900	102,900
Redeemable Non-controlling Interests
Balance		800
Investment by redeemable non-controlling interests		1,445
Adjustment to redemption value - Noncontrolling interests		912
Portion of loss attributable to non-controlling interest		(869)
Foreign currency translation adjustments		(42)
Balance	$ 2,246	2,246
Stock-based compensation expense		19,000
Capitalized stock-based compensation associated with internal-use software projects		$ 700