Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015
Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 37,573,000	$ 10,563,000	$ 11,453,000
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on short-term investments (net of tax of $111,000, $(8,000), and $16,000, respectively)	196,000	(13,000)	24,000
Foreign currency translation loss	(2,785,000)	(2,321,000)	(1,665,000)
Total other comprehensive loss, net of tax	(2,589,000)	(2,334,000)	(1,641,000)
Comprehensive income	$ 34,984,000	$ 8,229,000	$ 9,812,000