Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Mar. 31, 2014
Current assets:
Cash and cash equivalents	$ 106,704	$ 102,076
Marketable securities	87,967	75,234
Accounts receivable, net of allowance for doubtful accounts of $177 and $313 at December 31, 2014 and March 31, 2014, respectively	83,415	60,518
Inventories	10,274	12,580
Prepaid income taxes	2,864	1,012
Deferred income taxes	14,174	15,846
Prepaid expenses and other current assets	9,846	11,496
Total current assets	315,244	278,762
Fixed assets, net	23,016	23,098
Goodwill	200,271	203,446
Intangible assets, net	52,469	58,513
Long-term marketable securities	46,055	41,484
Other assets	1,873	2,460
Total assets	638,928	607,763
Current liabilities:
Accounts payable	10,927	11,541
Accrued compensation	39,369	34,901
Accrued other	11,026	6,430
Income taxes payable	0	791
Deferred revenue	107,595	109,301
Total current liabilities	168,917	162,964
Other long-term liabilities	2,147	2,370
Deferred tax liability	2,679	2,757
Accrued long-term retirement benefits	1,586	1,581
Long-term deferred revenue	27,036	24,639
Contingent liabilities, net of current portion	4,445	4,291
Total liabilities	206,810	198,602
Commitments and contingencies (Note 11)
Preferred stock, $0.001 par value:
5,000,000 shares authorized; no shares issued or outstanding at December 31, 2014 and March 31, 2014	0	0
Common stock, $0.001 par value:
150,000,000 shares authorized; 50,717,718 and 49,922,959 shares issued and 41,217,480 and 41,165,784 shares outstanding at December 31, 2014 and March 31, 2014, respectively	51	50
Additional paid-in capital	292,059	273,574
Accumulated other comprehensive income (loss)	(1,552)	2,772
Treasury stock at cost, 9,500,238 and 8,757,175 shares at December 31, 2014 and March 31, 2014, respectively	(149,345)	(117,802)
Retained earnings	290,905	250,567
Total stockholders’ equity	432,118	409,161
Total liabilities and stockholders’ equity	$ 638,928	$ 607,763