CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income		$ 6,330	$ 6,890
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		1,955	1,692
Investment premium amortization, net		240	154
Net loss on disposals of property and equipment		20	26
Foreign exchange (gain) loss		(618)	199
Share-based compensation expense		3,111	2,819
Excess tax benefits from share-based awards	[1]	0	(132)
Deferred income taxes		(714)	(396)
Equity in net loss of unconsolidated affiliate		34	34
Changes in assets and liabilities:
Receivables, net		(3,327)	(914)
Inventories		(1,853)	(2,123)
Prepaid expenses and other current assets		478	2,284
Other assets		(973)	(1,447)
Accounts payable		2,726	1,103
Accrued payroll and related expenses		(954)	(419)
Accrued taxes		3,522	739
Other liabilities		1,409	(22)
Deferred revenue		(271)	(216)
Warranty reserve		183	368
Net cash provided by operating activities		11,298	10,639
Cash flows from investing activities:
Purchases of available-for-sale investments		(4,037)	0
Purchases of held-to-maturity investments		(23,588)	(11,369)
Proceeds from maturities and redemptions of available-for-sale investments		1,700	1,000
Proceeds from maturities and redemptions of held-to-maturity investments		20,337	8,425
Purchases of property and equipment		(1,653)	(2,578)
Cash paid for investment in unconsolidated affiliate		0	(2,999)
Net cash used in investing activities		(7,241)	(7,521)
Cash flows from financing activities:
Tax withholdings related to net share settlements of restricted stock units		(1,354)	(1,103)
Excess tax benefits from share-based awards	[1]	0	132
Dividends paid		(3,172)	(2,700)
Net cash used in financing activities		(4,526)	(3,671)
Effect of exchange rate changes on cash and cash equivalents		610	(244)
Net increase (decrease) in cash and cash equivalents		141	(797)
Cash and cash equivalents at beginning of period		91,332	88,323
Cash and cash equivalents at end of period		91,473	87,526
Supplemental disclosure of cash flow information:
Cash paid for income taxes, net of refunds		(660)	718
Supplemental disclosure of non-cash flow information:
Change in unrealized gain (loss) on investments, net of tax		(10)	9
Transfers of equipment between inventory and property and equipment, net		304	1,537
Net change in capitalized share-based compensation		10	(77)
Common stock withheld for employee taxes in connection with share-based compensation		1,354	1,103
Repayment of notes payable by credits from municipal agency		$ 25	$ 25

[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 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."