Stock-Based Compensation - Additional Information (Detail) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2015
Restricted Stock Units (RSUs)
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Vesting period		3 years
Performance-based RSUs awarded based on achievement of development goals			203,258
Performance Shares
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Vesting period			4 years
Number of common stock earned per share			100.00%
Consecutive trading period required to earn PSU			45 days
Vesting rights			At any time during the four years following the date of the grant, a portion of the PSUs will vest one year after the date the average closing price of our Common Stock on the NASDAQ Global Select Market is above $50.00 per share for 45 consecutive trading days, and the remaining portion of the grant will vest one year after the date the average closing price of our Common Stock is above $60.00 per share for 45 consecutive trading days
Performance-based RSUs awarded based on achievement of development goals	16,058		165,000
Performance Shares | Maximum
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Performance-based RSUs awarded based on achievement of development goals, available for grant	69,625		69,625
Performance Shares | $50 Vesting Hurdle
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Minimum average market closing price to earn PSU			$ 50.00
Performance Shares | $60 Vesting Hurdle
Deferred Compensation Arrangement With Individual Share Based Payments [Line Items]
Minimum average market closing price to earn PSU			$ 60.00