CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands		9 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities:
Net income		$ 17,157	$ 25,166
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		5,920	5,329
Investment premium amortization, net		805	439
Net loss on disposals of property and equipment		25	81
Foreign exchange (gain) loss		(907)	755
Share-based compensation expense		10,191	8,317
Excess tax benefits from share-based awards	[1]	0	(346)
Deferred income taxes		2,559	(604)
Equity in net loss of unconsolidated affiliate		118	34
Gain on sale of equity method investment		0	(6,053)
Changes in assets and liabilities:
Receivables, net		324	729
Inventories		(5,128)	(8,121)
Prepaid expenses and other current assets		(1,318)	181
Other assets		(1,596)	(4,340)
Accounts payable		5,611	1,646
Accrued payroll and related expenses		679	(2,165)
Accrued taxes		(2,165)	(755)
Other liabilities		4,793	1,704
Deferred revenue		(543)	(713)
Warranty reserve		635	985
Net cash provided by operating activities		37,160	22,269
Cash flows from investing activities:
Purchases of available-for-sale investments		(68,415)	(2,991)
Purchases of held-to-maturity investments		(33,597)	(40,772)
Proceeds from maturities and redemptions of available-for-sale investments		19,340	3,300
Proceeds from maturities and redemptions of held-to-maturity investments		42,462	29,919
Purchases of property and equipment		(4,794)	(8,014)
Acquisitions, net of cash acquired		0	(785)
Cash paid for investment in unconsolidated affiliate		0	(2,999)
Proceeds from sale of equity method investment		0	8,526
Net cash used in investing activities		(45,004)	(13,816)
Cash flows from financing activities:
Tax withholdings related to net share settlements of restricted stock units		(2,521)	(2,188)
Excess tax benefits from share-based awards	[1]	0	346
Dividends paid		(9,980)	(8,559)
Net cash used in financing activities		(12,501)	(10,401)
Effect of exchange rate changes on cash and cash equivalents		915	(722)
Net decrease in cash and cash equivalents		(19,430)	(2,670)
Cash and cash equivalents at beginning of period		91,332	88,323
Cash and cash equivalents at end of period		71,902	85,653
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds		11,598	14,836
Supplemental disclosure of non-cash flow information:
Change in unrealized gain (loss) on investments, net of tax		(52)	(4)
Transfers of equipment between inventory and property and equipment, net		1,678	4,148
Net change in capitalized share-based compensation		38	(109)
Common stock withheld for employee taxes in connection with share-based compensation		2,521	2,188
Repayment of notes payable by credits from municipal agency		$ 76	$ 76

[1] The Company adopted Accounting Standards Update ("ASU") No. 2016-09, "Improvements to Employee Share-based Payment Accounting" ("ASU 2016-09"), during the first quarter of fiscal 2018. This standard eliminates the requirement to reclassify cash flows related to excess tax benefits from operating activities to financing activities on the statements of cash flows. The Company adopted the guidance prospectively effective April 1, 2017. The adoption of ASU 2016-09 is discussed further in Note 2, "Summary of Significant Accounting Policies."