CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net income	$ 27,177	$ 32,716	$ 31,630
Other comprehensive income (loss):
Net change in unrealized gain (loss) on investments	(216)	(8)	2
Tax provision (benefit) on other comprehensive income (loss)	(51)	(3)	1
Other comprehensive income (loss), net of tax	(165)	(5)	1
Comprehensive income	$ 27,012	$ 32,711	$ 31,631