Stockholders' Equity (Details1) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) $ / shares shares
Summary of stock option activity
Number of Shares, Outstanding-December 31, 2015 | shares	2,582,517
Number Of Shares, Assumed Options From Acquisition | shares	33,586
Number of Shares, Granted | shares	7,236
Number of Shares, Exercised | shares	(168,102)
Number of Shares, Forfeited or expired | shares	(18,313)
Number of Shares, Outstanding-June 30, 2016 | shares	2,436,924
Number of Shares, Options vested and expected to vest as of June 30, 2016 | shares	2,377,197	[1]
Number of Shares, Options vested and exercisable as of June 30, 2016 | shares	1,805,355
Stock option activity, weighted average exercise price (in dollars per share)
Weighted- Average Exercise Price, Outstanding-December 31, 2015 | $ / shares	$ 102.64
Weighted Average Exercise Price, Assumed Options From Acquisition | $ / shares	11.31
Weighted- Average Exercise Price, Granted | $ / shares	109.97
Weighted- Average Exercise Price, Exercised | $ / shares	28.51
Weighted- Average Exercise Price, Forfeited or expired | $ / shares	183.06
Weighted- Average Exercise Price, Outstanding-June 30, 2016 | $ / shares	105.92
Weighted- Average Exercise Price, Options vested and expected to vest as of June 30, 2016 | $ / shares	103.65	[1]
Weighted- Average Exercise Price, Options vested and exercisable as of June 30, 2016 | $ / shares	$ 76.17
Weighted average remaining contractual term, outstanding	5 years 6 months 11 days
Weighted average remaining contractual term, options vested and expected to vest	5 years 5 months 19 days	[1]
Weighted average remaining contractual, options vested and exercisable	4 years 9 months 4 days
Aggregate Intrinsic Value, Outstanding-June 30, 2016 | $	$ 229,935
Aggregate Intrinsic Value, Options vested and expected to vest as of June 30, 2016 | $	228,429	[1]
Aggregate Intrinsic Value, Options vested and exercisable as of June 30, 2016 | $	$ 213,845
Microsoft Agreement And Plan Of Merger [Member] | Disposal Group [Member]
Summary of stock option activity
Number of Shares, Exercised | shares	(600,476)
Stock option activity, weighted average exercise price (in dollars per share)
Disposal group, proposed Merger Agreement, stock conversion price | $ / shares	$ 196.00

[1] Of the options that are vested and expected to vest as of June 30, 2016, 600,476 shares have an exercise price above $196.00 and will be canceled for no payment at the effective time of the Merger. See Note 1, Description of Business and Basis of Presentation, for additional information regarding share conversion details upon consummation of the Merger.