Stockholders' Equity - Schedule of Common Stock Reserved for Future Issuance Under Equity Incentive Plans (Detail)	Jun. 30, 2022 shares
Class Of Stock [Line Items]
Total reserved shares of common stock	25,920,624
2014 Equity Incentive Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	19,762,888
2018 Inducement Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	5,367,281
2014 Employee Stock Purchase Plan
Class Of Stock [Line Items]
Total reserved shares of common stock	790,455