Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation - Additional Information (Details)

v3.19.1
Stock-Based Compensation - Additional Information (Details) - USD ($)
3 Months Ended 10 Months Ended
Mar. 31, 2019
Mar. 31, 2019
Dec. 31, 2018
Jun. 30, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Number of options granted 578,000      
Maximum number of shares issued upon exercise of incentive stock options 1,104,476 1,104,476    
Common stock, shares issued 19,118,421 19,118,421 19,114,421  
Weighted average grant date fair value of options granted $ 22.50      
Total intrinsic value of exercised stock options $ 78,000      
Early Exercise Stock Purchase Agreements        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period 36 months      
Nonvested common shares outstanding 56,038 56,038 68,349  
Percentage of underlying option shares whose right to purchase lapses after applicable vesting commencement date 25.00%      
Right to repurchase shares underlying shares 0.0208      
Restricted Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period 4 years      
Nonvested common shares outstanding 5,227 5,227 20,908  
2018 Equity Incentive Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for future issuance 2,179,866 2,179,866    
Number of shares will increase automatically through every year on specified date --01-01      
Number of shares increase automatically continuing through maximum period beginning on January 1, 2019 and continuing through and including January 1, 2028      
2018 Equity Incentive Plan | Common Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Maximum number of shares available for issuance 1,600,692 1,600,692    
Increase in number of shares reserved for issuance as percentage of total number of shares of capital stock outstanding on last date of preceding calendar year 5.00%      
2018 Equity Incentive Plan | Maximum [Member] | Common Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Maximum number of shares available for issuance 4,000,000 4,000,000    
2018 Equity Incentive Plan | Employee options        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Number of options granted   663,621    
2018 Equity Incentive Plan | Restricted Stock Units        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Number of RSU granted   10,189    
2018 Equity Incentive Plan | Incentive Stock Options | Maximum [Member] | Common Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Maximum number of shares issued upon exercise of incentive stock options 12,500,000 12,500,000    
2015 Equity Incentive Plan        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Vesting period 4 years      
Options to purchase of common stock outstanding 2,091,845 2,091,845    
Weighted average grant date fair value of options granted $ 15.79      
Total intrinsic value of exercised stock options $ 78,000      
2015 Equity Incentive Plan | Maximum [Member]        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Options granted expiry period 10 years      
2018 Employee Stock Purchase Plan | Common Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Shares available for future issuance 391,144 391,144   200,000
Common stock, shares issued 0 0    
Authorized an offering beginning period Nov. 16, 2018      
Authorized an offering ending period May 15, 2019      
2018 Employee Stock Purchase Plan | Maximum [Member] | Common Stock        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]        
Percentage of annual increase in number of common stock shares 1.00%      
Annual increase in number of common stock shares 375,000      
Option price per share of common stock at fair market value 85.00%