Basis of Presentation and Significant Accounting Policies - Summary of Product Revenue Allowance and Reserve Categories (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2017 USD ($)
Product Revenue Allowance and Reserves
Product Revenue Allowance and Reserve Categories
Beginning balance	$ 0
Provision related to sales in the current year	432
Credit and payments made	0
Ending balance	432
Chargebacks, Discounts, and Fees
Product Revenue Allowance and Reserve Categories
Beginning balance	0
Provision related to sales in the current year	271
Credit and payments made	0
Ending balance	271
Government and other rebates
Product Revenue Allowance and Reserve Categories
Beginning balance	0
Provision related to sales in the current year	86
Credit and payments made	0
Ending balance	86
Returns
Product Revenue Allowance and Reserve Categories
Beginning balance	0
Provision related to sales in the current year	75
Credit and payments made	0
Ending balance	$ 75