Subsequent Event - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Mar. 31, 2015
Subsequent Event [Line Items]
Net product sales	$ 7,780	$ 12,862	$ 26,067	$ 37,704
Customer Concentration Risk | Customer One
Subsequent Event [Line Items]
Net product sales	$ 3,300		$ 16,500		$ 39,500
Sales Revenue, Goods, Net | Customer Concentration Risk | Customer One
Subsequent Event [Line Items]
Concentration risk, percentage	42.50%		63.40%		57.30%