Summary of Significant Accounting Policies - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Costs and expenses:
Total share-based compensation	$ 16,102	$ 12,196	$ 7,598
Income tax benefit	(3,859)	(4,125)	(2,637)
Decrease in net income	12,243	8,071	4,961
Cost of Revenue
Costs and expenses:
Total share-based compensation	1,252	938	514
Research and Development Costs
Costs and expenses:
Total share-based compensation	2,919	2,038	973
Selling, General and Administrative
Costs and expenses:
Total share-based compensation	$ 11,931	$ 9,220	$ 6,111