Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands	3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Cash flows from operating activities:
Net income	$ 2,399	$ 7,145
Adjustments to reconcile net income to cash provided by operating activities, net of the effects of the acquisition of Psytechnics:
Depreciation and amortization	3,781	3,472
Loss on disposal of fixed assets	70	18
Share-based compensation expense associated with equity awards	2,159	1,178
Deferred income taxes	230	1,174
Changes in assets and liabilities
Accounts receivable	21,899	25,238
Inventories	(666)	(783)
Prepaid income taxes	(2,171)	2,288
Prepaid expenses and other current assets	603	914
Other assets	57	28
Accounts payable	(3,147)	1,214
Accrued compensation and other expenses	(9,268)	(6,714)
Deferred revenue	(9,627)	(11,318)
Net cash provided by operating activities	6,319	23,854
Cash flows from investing activities:
Purchase of marketable securities	(40,595)	(2,265)
Proceeds from maturity of marketable securities	32,253	17,404
Purchase of fixed assets	(3,707)	(2,093)
Acquisition of Psytechnics, net of cash acquired	(16,945)	0
Net cash provided by (used in) investing activities	(28,994)	13,046
Cash flows from financing activities:
Proceeds from the exercise of stock options	146	143
Repurchase of vested RSU's	(1,426)	0
Repayment of long-term debt	(3,750)	(2,500)
Excess tax benefit from stock options exercised	10	198
Net cash used in financing activities	(5,020)	(2,159)
Net increase (decrease) in cash and cash equivalents	(27,695)	34,741
Cash and cash equivalents, beginning of period	67,168	63,322
Cash and cash equivalents, end of period	39,473	98,063
Supplemental disclosure of non-cash activities:
Additions to property, plant and equipment included in accounts payable	$ 648	$ 0