Annual report pursuant to Section 13 and 15(d)

Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options (Detail)

v3.20.1
Common Stock - Summary of Stock Options Outstanding Regarding Number of Common Shares Issuable upon Exercise of Outstanding Options (Detail)
 12 Months Ended
Dec. 31, 2019
$ / shares
shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Number of Outstanding Options | shares 1,010,583
Exercise Price Range, Weighted Average Exercise Price $ 10.05
Exercise Price Range, Weighted Average Remaining Contractual Life 8 years 8 months 8 days
Range one [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1.42
Exercise Price Range, Upper Range Limit $ 1.99
Exercise Price Range, Number of Outstanding Options | shares 302,100
Exercise Price Range, Weighted Average Exercise Price $ 1.42
Exercise Price Range, Weighted Average Remaining Contractual Life 9 years 29 days
Range two [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 2.00
Exercise Price Range, Upper Range Limit $ 2.97
Exercise Price Range, Number of Outstanding Options | shares 386,650
Exercise Price Range, Weighted Average Exercise Price $ 2.56
Exercise Price Range, Weighted Average Remaining Contractual Life 8 years 8 months 19 days
Range three [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 2.98
Exercise Price Range, Upper Range Limit $ 3.37
Exercise Price Range, Number of Outstanding Options | shares 167,750
Exercise Price Range, Weighted Average Exercise Price $ 3.37
Exercise Price Range, Weighted Average Remaining Contractual Life 8 years 6 months 25 days
Range four [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 3.38
Exercise Price Range, Upper Range Limit $ 3.70
Exercise Price Range, Number of Outstanding Options | shares 8,250
Exercise Price Range, Weighted Average Exercise Price $ 3
Exercise Price Range, Weighted Average Remaining Contractual Life 9 years
Range five [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 3.71
Exercise Price Range, Upper Range Limit $ 16.46
Exercise Price Range, Number of Outstanding Options | shares 35,000
Exercise Price Range, Weighted Average Exercise Price $ 4
Exercise Price Range, Weighted Average Remaining Contractual Life 9 years
Range six [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 16.47
Exercise Price Range, Upper Range Limit $ 69.45
Exercise Price Range, Number of Outstanding Options | shares 104,910
Exercise Price Range, Weighted Average Exercise Price $ 28.90
Exercise Price Range, Weighted Average Remaining Contractual Life 7 years 6 months 29 days
Range seven [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 69.46
Exercise Price Range, Upper Range Limit $ 206.25
Exercise Price Range, Number of Outstanding Options | shares 2,190
Exercise Price Range, Weighted Average Exercise Price $ 186.98
Exercise Price Range, Weighted Average Remaining Contractual Life 5 years 6 months 25 days
Range eight [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 206.26
Exercise Price Range, Upper Range Limit $ 1,286.45
Exercise Price Range, Number of Outstanding Options | shares 853
Exercise Price Range, Weighted Average Exercise Price $ 465.93
Exercise Price Range, Weighted Average Remaining Contractual Life 4 years 5 months 19 days
Range nine [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1,286.46
Exercise Price Range, Upper Range Limit $ 1,348.05
Exercise Price Range, Number of Outstanding Options | shares 1,530
Exercise Price Range, Weighted Average Exercise Price $ 1,304.27
Exercise Price Range, Weighted Average Remaining Contractual Life 3 years 9 months 10 days
Range ten [Member]  
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]  
Exercise Price Range, Lower Range Limit $ 1,348.06
Exercise Price Range, Upper Range Limit $ 1,960.20
Exercise Price Range, Number of Outstanding Options | shares 1,350
Exercise Price Range, Weighted Average Exercise Price $ 1,605.51
Exercise Price Range, Weighted Average Remaining Contractual Life 1 year 7 months 13 days