Revenue Recognition - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2018	Mar. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Contract length	As a result of the short durations of the Company's customer contracts, which are typically effective for one year or less and have payment terms that are generally 30-60 days, these arrangements are not considered to have a significant financing component.
Sales and allowances period	30 days
Contract liability	$ 44,337	$ 23,156
Allowance for sales discounts
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Total Allowances	0	0
Allowance for chargebacks
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Total Allowances	16,064	7,727
Deferred Shipment Revenue
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Contract liability	0	0
Gift Cards
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Contract liability	3,309	3,105
Loyalty Programs
SEC Schedule, 12-09, Valuation and Qualifying Accounts Disclosure [Line Items]
Contract liability	$ 7,323	$ 5,477