Stockholders' Equity - Restricted Stock Awards, Restricted Stock Units and Performance-Based Restricted Stock Units - Additional Information (Detail) - Inducement Award Performance-Based Restricted Stock Units [Member]		12 Months Ended
	Aug. 23, 2017 USD ($) Tranche shares	Mar. 31, 2019 Tranche shares	Apr. 24, 2017 shares
Class Of Stock [Line Items]
Number of tranches | Tranche	5
Award vesting percentage		100.00%
Number of tranches vested | Tranche		0
Grant date fair values of tranches | $	$ 165,000
Maximum [Member]
Class Of Stock [Line Items]
Number of shares allocated	208,822
Share-based Compensation Award, Tranche One [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2018
Share-based Compensation Award, Tranche One [Member] | Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Share-based Compensation Award, Tranche One [Member] | Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Share-based Compensation Award, Tranche Two [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2019
Share-based Compensation Award, Tranche Two [Member] | Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Share-based Compensation Award, Tranche Two [Member] | Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Share-based Compensation Award, Tranche Three [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2020
Share-based Compensation Award, Tranche Three [Member] | Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Share-based Compensation Award, Tranche Three [Member] | Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Share Based Compensation Award Tranche Four [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2021
Share Based Compensation Award Tranche Four [Member] | Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Share Based Compensation Award Tranche Four [Member] | Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
Share Based Compensation Award Tranche Five [Member]
Class Of Stock [Line Items]
Award vesting percentage	20.00%
Stock units vesting year	2020
Share based compensation arrangement, number of shares vested		41,764
Share based compensation arrangement, number of shares forfeited		8,352
Share based compensation arrangement, number of shares eligible to vest upon future performance		158,706
Share based compensation arrangement amendment description and terms		Based on the amendment to the vesting criteria, the remaining 158,706 units eligible to vest upon future performance were divided into three separate but equal tranches with independent vesting criteria based on the achievement of certain regulatory milestones.
Share Based Compensation Award Tranche Five [Member] | Minimum [Member]
Class Of Stock [Line Items]
Award vesting percentage	0.00%
Share Based Compensation Award Tranche Five [Member] | Maximum [Member]
Class Of Stock [Line Items]
Award vesting percentage	120.00%
CEO [Member]
Class Of Stock [Line Items]
Number of shares allocated			208,822