Quarterly report pursuant to Section 13 or 15(d)

Stock Warrants - Schedule of Warrants Outstanding (Detail)

v3.20.1
Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares
3 Months Ended
Mar. 31, 2020
Dec. 31, 2019
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 3,033,196 3,033,910
Weighted-average exercise price per share $ 22.60 $ 22.61
Placement Agent Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 18,915 18,915
Other Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants [1] 14,636 15,350
Exercise Price Less Than or Equal to $20.00 [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,600,216  
Expiration Start Date Sep. 01, 2021  
Expiration End Date Jul. 25, 2022  
Exercise Price Greater Than or Equal to $ 20.00 [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,432,980  
Expiration Start Date Apr. 12, 2020  
Expiration End Date Jan. 05, 2022  
Minimum [Member] | Exercise Price Less Than or Equal to $20.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices $ 20.00  
Maximum [Member] | Exercise Price Greater Than or Equal to $ 20.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices $ 20.00  
2016 Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,400,000 1,400,000
2017 Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,599,645 1,599,645
[1] Other warrants are comprised of warrants issued prior to the Company’s IPO, generally in exchange for services rendered to the Company.