CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net income	$ 25,166	$ 22,769
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	5,329	5,192
Investment premium amortization, net	439	898
Net loss on disposals of property and equipment	81	32
Impairment loss of intangible assets	0	13
Foreign exchange (gain) loss	755	(134)
Share-based compensation expense	8,317	8,236
Excess tax benefits from share-based awards	(346)	(1,628)
Deferred income taxes	(604)	(263)
Equity in net (income) loss of unconsolidated affiliate	34	(56)
Gain on sale of equity method investment	(6,053)	0
Changes in assets and liabilities:
Receivables, net	729	(2,400)
Inventories	(8,121)	159
Prepaid expenses and other current assets	181	(2,369)
Other assets	(4,340)	(485)
Accounts payable	1,646	155
Accrued payroll and related expenses	(2,165)	(4,189)
Accrued taxes	(755)	(4,539)
Other liabilities	1,704	(5,372)
Deferred revenue	(713)	(488)
Warranty reserve	985	(62)
Net cash provided by operating activities	22,269	15,469
Cash flows from investing activities:
Purchases of available-for-sale investments	(2,991)	(1,726)
Purchases of held-to-maturity investments	(40,772)	(41,064)
Proceeds from maturities and redemptions of available-for-sale investments	2,300	0
Proceeds from maturities and redemptions of held-to-maturity investments	30,919	19,212
Purchases of property and equipment	(8,014)	(4,405)
Acquisitions, net of cash acquired	(785)	(1,131)
Cash paid for investment in unconsolidated affiliate	(2,999)	0
Proceeds from sale of equity method investment	8,526	0
Net cash used in investing activities	(13,816)	(29,114)
Cash flows from financing activities:
Tax withholdings related to net share settlements of restricted stock units	(2,188)	(5,237)
Excess tax benefits from share-based awards	346	1,628
Proceeds from the exercise of warrants	0	12
Dividends paid	(8,559)	(7,494)
Net cash used in financing activities	(10,401)	(11,091)
Effect of exchange rate changes on cash and cash equivalents	(722)	123
Net decrease in cash and cash equivalents	(2,670)	(24,613)
Cash and cash equivalents at beginning of period	88,323	107,015
Cash and cash equivalents at end of period	85,653	82,402
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	14,836	17,623
Supplemental disclosure of non-cash flow information:
Change in unrealized gain (loss) on investments, net of tax	(4)	(9)
Transfers of equipment between inventory and property and equipment, net	4,148	902
Net change in capitalized share-based compensation	(109)	60
Common stock withheld for employee taxes in connection with share-based compensation	2,188	5,237
Repayment of notes payable by credits from municipal agency	$ 76	$ 76