Share-Based Compensation - Stock Option Activity under Stock Option Plans (Details) - USD ($)	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Number of Shares
Beginning balance (in shares)	737,931
Granted (in shares)	0
Exercised (in shares)	(90,566)
Cancelled (in shares)	(189,853)
Ending balance (in shares)	457,512
Vested and Expected to Vest (in shares)	457,512
Exercisable (in shares)	457,512
Weighted-Average Exercise Price
Beginning balance (in dollars per share)	$ 20.99
Granted (in dollars per share)		$ 8.13
Exercised (in dollars per share)	$ 15.70
Cancelled (in dollars per share)	26.00
Ending balance (in dollars per share)	19.96
Vested and Expected to Vest (in dollars per share)	19.96
Exercisable (in dollars per share)	$ 19.96
Weighted Average Remaining Contractual Term
Outstanding	3 years 3 months 22 days
Vested and Expected to Vest	3 years 3 months 22 days
Exercisable	3 years 3 months 22 days
Aggregate Intrinsic Value
Outstanding	$ 2,976,604
Vested and Expected to Vest	2,976,604
Exercisable	$ 2,976,604