Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation - Restricted Stock Units - Additional Information (Detail)

v3.10.0.1
Stock Based Compensation - Restricted Stock Units - Additional Information (Detail)
12 Months Ended
Dec. 31, 2018
USD ($)
shares
Restricted Stock Units (RSUs) [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Employee service share-based compensation, nonvested awards, compensation not yet recognized, share-based awards other than options | $ $ 25,810,914
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition 2 years 3 months 18 days
Non-Employee Equity Compensation Plan 2014 [Member] | 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 175,826
Non-Employee Equity Compensation Plan 2014 [Member] | Restricted Stock Units (RSUs) [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based compensation arrangement by share-based payment award, award vesting period 1 year
Non-Employee Equity Compensation Plan 2014 [Member] | Restricted Stock Units (RSUs) [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based compensation arrangement by share-based payment award, award vesting period 4 years
2013 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Employee [Member] | Common Stock [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 856,975
2013 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Minimum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based compensation arrangement by share-based payment award, award vesting period 1 year
2013 Equity Incentive Plan [Member] | Restricted Stock Units (RSUs) [Member] | Maximum [Member]  
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Share-based compensation arrangement by share-based payment award, award vesting period 4 years
2017 Equity Inducement Plan [Member] | Employee [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 345,500
Share-based compensation arrangement by share-based payment award, award vesting period 4 years