Stock Plans (Details 3) (USD $)	9 Months Ended
	Sep. 30, 2012
Share-based award activity under the 2011 plan
Number of Stock Options Outstanding, Outstanding - September 30, 2012	2,213,529
Weighted-Average Exercise Price, Outstanding - September 30, 2012	$ 11.97
Weighted Average Grant Date Fair Value, Balances - January 1, 2012
Weighted average grant date fair value additional shares added to the pool
2011 Plan [Member]
Share-based award activity under the 2011 plan
Shares Available for Grant, Outstanding - January 1, 2012	1,886,296
Shares Available for Grant, Additional shares added to the pool	919,127
Shares Available for Grant, Granted	(965,952)
Shares Available for Grant, Cancelled or forfeited	183,229
Shares Available for Grant, Outstanding - September 30, 2012	2,022,700
Number of Stock Options Outstanding, Outstanding - January 1, 2012	2,871,005
Number of Stock Options Outstanding, Granted	580,184
Number of Stock Options Outstanding, Exercised	(1,059,806)
Number of Stock Options Outstanding, Cancelled or forfeited	(177,854)
Number of Stock Options Outstanding, Outstanding - September 30, 2012	2,213,529
Weighted-Average Exercise Price, Outstanding - January 1, 2012	$ 4.15
Weighted Average Exercise Price, Granted	$ 31.79
Weighted Average Exercise Price, Exercised or released	$ 2.00
Weighted Average Exercise Price, Cancelled or forfeited	$ 9.91
Weighted-Average Exercise Price, Outstanding - September 30, 2012	$ 11.97
Weighted Average Grant Date Fair Value, Granted	$ 31.14
Weighted Average Grant Date Fair Value, Cancelled or forfeited	$ 34.02
Weighted Average Grant Date Fair Value, Balances - September 30, 2012	$ 31.10
Restricted Stock Units [Member] | 2011 Plan [Member]
Share-based award activity under the 2011 plan
Number of Restricted Stock Units Outstanding, Granted	385,768
Number of Restricted Stock Units Outstanding, Cancelled or Forfeited	(5,375)
Number of Restricted Stock Units Outstanding, Balances - September 30, 2012	380,393