XML 87 R73.htm IDEA: XBRL DOCUMENT v3.8.0.1
Share-Based Compensation - Summary of Stock Option Activity (Detail) - USD ($)
$ / shares in Units, $ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]      
Beginning balance of Outstanding, Options 3,085,888 2,657,723 3,781,964
Granted, Options 365,709 915,122 848,705
Exercised, Options (288,618) (89,773) (303,035)
Forfeited, Options (75,426) (120,964) (1,278,150)
Cancelled, Options (219,500) (276,220) (391,761)
Ending balance of Outstanding, Options 2,868,053 3,085,888 2,657,723
Exercisable, Options 1,788,346    
Beginning balance of Outstanding, Weighted Average Exercise Price $ 11.18 $ 14.27 $ 12.88
Granted, Weighted Average Exercise Price 8.67 4.81 4.83
Exercised, Weighted Average Exercise Price 8.18 4.17 2.73
Forfeited, Weighted Average Exercise Price 6.97 5.11 4.60
Cancelled, Weighted Average Exercise Price 29.67 24.69 20.87
Ending balance of Outstanding, Weighted Average Exercise Price 9.86 $ 11.18 $ 14.27
Exercisable, Weighted Average Exercise Price $ 12.28    
Outstanding, Weighted Average Remaining Contractual Term 6 years 10 days    
Exercisable, Weighted Average Remaining Contractual Term 4 years 7 months 17 days    
Exercised, Aggregate Intrinsic Value $ 250 $ 189 $ 620
Outstanding, Aggregate Intrinsic Value 14,341    
Exercisable, Aggregate Intrinsic Value $ 7,622