Revenue Recognition - Schedule of Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2018	Mar. 31, 2018
Contract Asset
Balance as of March 31, 2018	$ 16,355	$ 11,251
Change in estimate of sales returns	29,653
Actual returns	(24,549)
Balance as of December 31, 2018	16,355
Contract Liability
Balance as of March 31, 2018	44,337	$ 23,156
Change in estimate of sales returns	104,009
Actual returns	(82,828)
Balance as of December 31, 2018	$ 44,337