Net Loss Per Share - Summary of Basic and Diluted Net Loss Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Numerator:
Net loss	$ (70,202)	$ (34,747)	$ (126,979)	$ (65,290)
Denominator:
Weighted average common stock outstanding—basic	37,361,129	32,062,298	37,315,393	31,835,194
Dilutive effect of shares of common stock equivalents resulting from common stock options and restricted stock units	0	0	0	0
Weighted average common stock outstanding—diluted	37,361,129	32,062,298	37,315,393	31,835,194
Net loss per share—basic and diluted	$ (1.88)	$ (1.08)	$ (3.40)	$ (2.05)