Quarterly report pursuant to Section 13 or 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.19.3
Stockholders' Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended
Aug. 02, 2018
Aug. 31, 2019
Sep. 30, 2019
Sep. 30, 2018
Sep. 30, 2019
Sep. 30, 2018
Dec. 31, 2013
Jul. 31, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Stock-based compensation     $ 1,200,000 $ 900,000 $ 3,200,000 $ 2,900,000    
Restricted Stock Units (RSUs) [Member]                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Number of shares granted         1,600,000      
One-Time Option Exchange [Member]                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Stock options exchange description         The participants received one new RSU for every two stock options tendered for exchange.      
Number of stock options exchanged   3,200,375            
Additional stock compensation expense expected service term   1 year            
One-Time Option Exchange [Member] | Restricted Stock Units (RSUs) [Member]                
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                
Number of shares granted   1,600,186            
Shares granted, vesting period   1 year            
Incremental value of the modifications   $ 100,000            
Series B Preferred Stock [Member] | Lender Warrants [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   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   $ 100,000