Annual report pursuant to Section 13 and 15(d)

Stock-Based Compensation - Additional Information (Detail)

v3.20.2
Stock-Based Compensation - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 12 Months Ended
Apr. 01, 2029
Dec. 01, 2019
Dec. 31, 2019
Mar. 31, 2020
Mar. 31, 2019
Dec. 18, 2019
Jul. 31, 2019
Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Common shares reserved for grant       5,283,520 3,478,728      
Common shares available for future issuance       34,917,408 3,667,997      
Weighted average fair value at the grant date       $ 5.54 $ 2.76      
Unrecognized equity-based compensation related to unvested stock options       $ 17,300        
Remaining weighted average service period for recognition       3 years 1 month 6 days        
Share based compensation expense       $ 6,788 $ 31      
Stock options exercised       0        
Roivant Sciences Ltd. (RSL) [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Share based compensation expense       $ 200 $ 1,300      
2018 Equity Incentive Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Common shares reserved for grant             4,768,396 3,667,997
Share based compensation arrangement by share based payment award number of shares assumed and converted into options to purchase shares       3,657,408   4,408,287    
2019 Equity Incentive Plan [Member]                
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                
Common shares reserved for grant       216,480        
Share based compensation, description   For grants of incentive stock options, if the grantee owns, or is deemed to own, 10% or more of the total voting power of the Company, then the exercise price shall be 110% of the fair market value of the Company’s common stock on the date of grant and the option will have a five-year contractual term.            
Share based compensation, contractual term     ten-year          
Common shares available for future issuance   5,500,000   5,283,520        
Percentage of common stock outstanding 4.00%              
Option to Purchase of common stock       0        
Maximum number of shares issued   16,500,000