Stock Based Compensation - Summary of Stock Option Plan (Detail)	9 Months Ended
	Sep. 30, 2016 $ / shares shares
Shares
Number of Shares, Outstanding, Beginning balance (in shares) | shares	1,507,765
Number of Shares, Granted (in shares) | shares	1,142,531
Number of shares, Cancelled/Forfeited (in shares) | shares	(55,683)
Number of Shares, Outstanding, Ending balance (in shares) | shares	2,594,613
Number of Shares, Options exercisable (in shares) | shares	641,814
Weighted Average Exercise Price Per Share
Weighted Average Exercise Price Per Share, Outstanding, Beginning balance (usd per share) | $ / shares	$ 21.07
Weighted Average Exercise Price Per Share, Granted (usd per share) | $ / shares	11.58
Weighted Average Exercise Price Per Share, Cancelled/Forfeited (usd per share) | $ / shares	14.36
Weighted Average Exercise Price Per Share, Outstanding, Ending balance (usd per share) | $ / shares	17.04
Weighted Average Exercise Price Per Share, options exercisable (usd per share) | $ / shares	$ 21.47