CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 14,811	$ 10,115
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,298	4,166
Investment premium amortization, net	546	301
Net loss on disposals of property and equipment	16	2
Impairment loss of intangible assets	13	0
Foreign exchange (gain) loss	(168)	564
Share-based compensation expense	5,839	4,527
Excess tax benefits from share-based awards	(1,444)	(859)
Deferred income taxes	(269)	(1,517)
Equity in net (income) loss of unconsolidated affiliate	(31)	32
Changes in assets and liabilities:
Receivables, net	606	(7,214)
Inventories	1,249	(3,223)
Prepaid expenses and other current assets	(1,391)	(815)
Other assets	(541)	(60)
Accounts payable	(23)	4,053
Accrued payroll and related expenses	(2,168)	4,148
Accrued taxes	(4,455)	(214)
Other liabilities	(5,954)	2,483
Deferred revenue	(326)	(441)
Warranty reserve	(332)	317
Net cash provided by operating activities	9,276	16,365
Cash flows from investing activities:
Purchases of held-to-maturity investments	(36,316)	(13,650)
Proceeds from maturities and redemptions of available-for-sale investments	0	498
Proceeds from maturities and redemptions of held-to-maturity investments	14,465	18,729
Purchases of property and equipment	(2,635)	(3,904)
Net cash provided by (used in) investing activities	(24,486)	1,673
Cash flows from financing activities:
Proceeds from the exercise of stock options	0	4
Tax withholdings related to net share settlements of restricted stock units	(4,851)	(2,884)
Excess tax benefits from share-based awards	1,444	859
Proceeds from the exercise of warrants	12	60
Dividends paid	(4,993)	(4,498)
Net cash used in financing activities	(8,388)	(6,459)
Effect of exchange rate changes on cash and cash equivalents	216	(574)
Net increase (decrease) in cash and cash equivalents	(23,382)	11,005
Cash and cash equivalents at beginning of period	107,015	73,589
Cash and cash equivalents at end of period	83,633	84,594
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds	13,897	7,138
Supplemental disclosure of non-cash flow information:
Change in unrealized gain (loss) on investments, net of tax	1	(13)
Transfers of equipment between inventory and property and equipment, net	546	1,223
Net change in capitalized share-based compensation	66	9
Common stock withheld for employee taxes in connection with share-based compensation	4,851	2,884
Repayment of notes payable by credits from municipal agency	$ 50	$ 50