Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.19.1
Stockholders' Equity - Additional Information (Detail) - USD ($)
3 Months Ended 12 Months Ended
Aug. 02, 2018
Mar. 31, 2019
Mar. 31, 2018
Dec. 31, 2013
Jul. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Stock-based compensation   $ 900,000 $ 1,000,000    
Lender Warrants [Member] | Series B convertible preferred stock [Member] | Term Loan One [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Warrant issued       111,112  
Exercise price of warrant per share       $ 0.90  
Warrant expiration date       Jul. 03, 2023  
Common Stock [Member] | Lender Warrants [Member] | Convertible promissory notes [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Exercise price of warrant per share         $ 7.43
Warrants exercisable         13,468
Sales Agreement with Stifel [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Number of shares sold under sales agreement   0      
Sales Agreement with Stifel [Member] | Maximum [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Common stock, value of shares issued $ 35,000,000        
Percentage of commission of gross sales price per share 3.00%        
Sales Agreement with Stifel [Member] | Other Assets [Member]          
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]          
Legal and accounting costs incurred   $ 100,000