Quarterly report pursuant to Section 13 or 15(d)

Stock Based Compensation - Equity Incentive Plan - Additional Information (Detail)

v3.19.3
Stock Based Compensation - Equity Incentive Plan - Additional Information (Detail) - USD ($)
9 Months Ended
Apr. 30, 2015
Sep. 30, 2019
May 16, 2018
Dec. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Employee contribution through payroll withholdings   $ 147,809    
Performance Share Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance     2,710,104  
Common stock, capital shares reserved for future issuance     1,400,000  
Share-based compensation arrangement by share-based payment award, number of shares available for grant   1,431,951    
Employee Stock Purchase Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, capital shares reserved for future issuance 600,000      
Share-based compensation arrangement by share-based payment award, number of shares available for grant   257,988    
Lowest percentage of annual compensation to be utilized by an employee for purchase of shares under the plan 1.00%      
Highest percentage of annual compensation to be utilized by an employee for purchase of shares under the plan 10.00%      
Maximum number of shares permitted to purchase 7,500      
Offering period 6 months      
Exercise price discount from fair value on offering date 85.00%      
Exercise price discount from fair value on exercise date 85.00% 15.00%    
Share-based compensation arrangement by share-based payment award, terms of award   In April 2015, the Company’s Board approved the ESPP, under which 600,000 shares of common stock were reserved for purchase by the Company’s employees, and on May 21, 2015, the Company’s stockholders approved the ESPP. Under the ESPP, employees may designate an amount not less than 1% but not more than 10% of their annual compensation for the purchase of Company shares. No more than 7,500 shares may be purchased by an employee under the ESPP during an offering period. An offering period shall be six months in duration commencing on or about January 1 and July 1 of each year. The exercise price of the purchase option will be the lesser of 85% of the fair market of the common stock on the first business day of the offering period and 85% of the fair market value of the common stock on the applicable exercise date.    
2013 Equity Incentive Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance     6,085,967  
Common stock, capital shares reserved for future issuance     1,600,000  
Common stock to be issued   1,697,263    
Non-Employee Equity Compensation Plan 2014 [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance     850,000  
Common stock, capital shares reserved for future issuance     250,000  
Common stock available to be issued   214,057    
2017 Equity Inducement Plan [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock available to be issued   303,469    
2017 Equity Inducement Plan [Member] | Restricted Stock Units (RSUs) [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Common stock, capital shares reserved for future issuance       600,000