XML 67 R55.htm IDEA: XBRL DOCUMENT v3.20.2
Fair Value of Financial Instruments - Additional Information (Detail) - USD ($)
6 Months Ended
Jun. 30, 2020
Dec. 31, 2019
Fair Value Of Financial Instruments [Line Items]    
Cash and cash equivalents $ 63,222,000 $ 29,906,000
Restricted cash 316,000 316,000
Short-term investments $ 0 19,978,000
Fair value of note payable to related party, description The fair value measurement of debt instruments is based on a discounted cash flow model and is sensitive to the change in yield (Level 3 in the fair value hierarchy  
Money Market Funds    
Fair Value Of Financial Instruments [Line Items]    
Cash and cash equivalents $ 63,200,000 29,900,000
Restricted cash $ 300,000 $ 300,000