Quarterly report pursuant to Section 13 or 15(d)

Stock Plan and Stock-Based Compensation - Additional Information (Detail)

v3.19.3
Stock Plan and Stock-Based Compensation - Additional Information (Detail) - 2013 Equity Incentive Plan [Member] - shares
3 Months Ended 9 Months Ended
Jan. 01, 2019
Sep. 30, 2019
Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Increase in shares reserved for issuance 2,378,259    
Shares available for grant   1,249,186 1,249,186
Employees, Directors and Consultant [Member]      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of option granted to employees   589,600 2,733,960