Subsequent Events - Additional Information (Detail) - Employee Stock Option [Member] - shares	May 08, 2019	Mar. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized		5,000,000
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized	3,000,000
Share-based compensation arrangement by share-based payment award, number of shares authorized	8,000,000