Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Detail)

v3.20.1
Summary of Significant Accounting Policies - Summary of Outstanding Potentially Dilutive Securities Excluded in Calculation of Diluted Net Loss Per Share (Detail) - shares
shares in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 2,765 5,406 7,946
ESPP shares pending issuance [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 0 8 5
Warrants to purchase common stock [Member] | Common Stock [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 13 13 150
Common stock options issued and outstanding [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 1,299 5,385 4,826
RSUs outstanding [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 1,453 0 0
Shares issuable upon conversion of convertible note payable [Member]      
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]      
Outstanding potentially dilutive securities 0 0 2,965