Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Restricted Stock Units - Additional Information (Detail)

v3.19.1
Stock-Based Compensation - Restricted Stock Units - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2019
Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized stock-based compensation expense related to to non-vested stock options and restricted stock units $ 10.2  
2017 Omnibus Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Restricted stock, vesting period 6 years  
Restricted Stock Units [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Total fair value vested $ 0.1 $ 0.0
Unrecognized stock-based compensation expense, expected recognition weighted-average period 45 months  
Restricted Stock Units [Member] | 2017 Omnibus Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Restricted stock, vesting period 5 years  
Employee Stock Options [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized stock-based compensation expense, expected recognition weighted-average period 51 months  
Nonemployee Restricted Stock Units [Member] | Cellectis [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Dividends $ 0.4 $ 0.7