Stock-Based Compensation - Summary of Stock Option Activity (Detail)	6 Months Ended
	Jun. 30, 2017 $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Shares Issuable Under Options, Beginning balance | shares	3,268,000
Shares Issuable Under Options, Granted | shares	879,000
Shares Issuable Under Options, Exercised | shares	(182,000)
Shares Issuable Under Options, Cancelled | shares	(89,000)
Shares Issuable Under Options, Ending balance | shares	3,876,000
Shares Issuable Under Options, Options vested and expected to vest at March 31, 2017 | shares	3,876,000
Shares Issuable Under Options, Options exercisable at March 31, 2017 | shares	1,353,000
Weighted Average Exercise Price, Beginning balance | $ / shares	$ 14.84
Weighted Average Exercise Price, Granted | $ / shares	22.03
Weighted Average Exercise Price, Exercised | $ / shares	8.01
Weighted Average Exercise Price, Cancelled | $ / shares	17.17
Weighted Average Exercise Price, Ending balance | $ / shares	17.60
Weighted Average Exercise Price, Options vested and expected to vest | $ / shares	17.60
Weighted Average Exercise Price, Options exercisable | $ / shares	$ 14.15