Common Stock - Summary of Common Stock Available for Future Issuance (Detail) - shares	Jun. 30, 2020	Dec. 31, 2019
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized	146,000,000	76,000,000
Common stock issued	1,488,489	1,488,489
Common stock outstanding	1,488,489	1,488,489
Common stock authorized and reserved for future issuance	14,948,249	7,289,543
Total common stock authorized and reserved for future issuance	18,239,357
Unreserved common stock available for future issuance	127,760,643
Employee Stock Option [Member]
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized and reserved for future issuance	1,073,044
Share-based Payment Arrangement [Member]
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized and reserved for future issuance	729,575
Series A Redeemable Convertible Preferred Stock [Member]
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized and reserved for future issuance	3,343,542	3,343,542
Series B Redeemable Convertible Preferred Stock [Member]
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized and reserved for future issuance	4,499,824	3,946,001
Series C Redeemable Convertible Preferred Stock [Member]
Disclosure of Common Stock Summary of Outstanding and Reserved for Future Issuance [Line Items]
Common stock authorized and reserved for future issuance	7,104,883