Annual report pursuant to Section 13 and 15(d)

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

v3.21.1
Stock Based Compensation - Equity Incentive Plan - Additional Information (Detail) - USD ($)
12 Months Ended
Apr. 30, 2015
Dec. 31, 2020
Dec. 31, 2019
May 26, 2020
Dec. 28, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Employee contribution through payroll withholdings   $ 417,546 $ 457,362    
2015 Performance Share Unit Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock, capital shares reserved for future issuance       700,000  
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance       3,410,104  
Common stock remain eligible to be issued   2,131,951      
Restricted Stock Units (RSUs) [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period   1,005,109      
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     250,000  
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance       850,000  
Common stock remain eligible to be issued   140,438      
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 have been reserved for purchase by the Company’s employees, subject to approval by the stockholders. On May 21, 2015, the Company’s stockholders approved the ESPP. Effective on May 26, 2020, the Company’s stockholders approved the amendment and restatement of the Employee Stock Purchase Plan to increase the number of shares reserved for issuance through equity-based instruments thereunder by 250,000 shares, bringing to 850,000 the total number of shares approved for issuance under that plan. 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 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.    
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period   275,312 178,003    
2013 Equity Incentive Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock, capital shares reserved for future issuance       1,200,000  
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance       7,285,967  
Common stock remain eligible to be issued   1,867,169      
Non-Employee Equity Compensation Plan 2014 [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock, capital shares reserved for future issuance       800,000  
Share-based compensation arrangement by share-based payment award, number of shares authorized for issuance       1,650,000  
Common stock remain eligible to be issued   998,971      
2017 Equity Inducement Plan [Member]          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Common stock remain eligible to be issued   139,276      
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