XML 118 R65.htm IDEA: XBRL DOCUMENT v3.8.0.1
Equity and Stock-based Compensation - Schedule of Allocated Stock-Based Compensation Expense (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation expense $ 37,539 $ 32,132 $ 27,681
Research and development [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation expense 21,807 19,070 16,987
General and administrative [Member]      
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]      
Total stock-based compensation expense $ 15,732 $ 13,062 $ 10,694