Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Summary of Stock Option Activity (Detail)

v3.19.2
Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
6 Months Ended
Jun. 30, 2019
Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Exercised, Shares (181,664) (622,982)
2014 EIP and Inducement Plan    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]    
Outstanding, Shares, beginning balance 6,276,999  
Granted, Shares 1,750,825  
Exercised, Shares (181,664)  
Forfeited or expired, Shares (554,431)  
Outstanding, Shares, ending balance 7,291,729  
Vested and expected to vest, Shares 7,291,729  
Exercisable, Shares 2,972,192  
Outstanding, Weighted Average Exercise Price, beginning balance $ 28.15  
Granted, Weighted Average Exercise Price 32.47  
Exercised, Weighted Average Exercise Price 18.13  
Forfeited or expired, Weighted Average Exercise price 33.29  
Outstanding, Weighted Average Exercise Price, ending balance 29.04  
Stock options vested and expected to vest, Weighted Average Exercise Price 29.04  
Exercisable, Weighted Average Exercise Price $ 24.40  
Outstanding, Weighted Average Remaining Contractual Term 5 years 6 months  
Stock options vested and expected to vest, Weighted Average Remaining Contractual Term 5 years 6 months  
Exercisable, Weighted Average Remaining Contractual Term 3 years 6 months  
Aggregate intrinsic value $ 8,693  
Vested and expected to vest, Aggregate Intrinsic Value 8,693  
Exercisable, Aggregate Intrinsic Value $ 5,697