Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2013
Current assets:
Cash and cash equivalents	$ 88,648	$ 99,930
Marketable securities	56,343	37,338
Accounts receivable, net of allowance for doubtful accounts of $147 and $971 at December 31, 2013 and March 31, 2013, respectively	74,263	73,900
Inventories	11,128	7,563
Deferred income taxes	9,419	9,538
Prepaid expenses and other current assets	8,800	9,043
Total current assets	248,601	237,312
Fixed assets, net	21,350	19,678
Goodwill	203,201	202,453
Intangible assets, net	59,827	63,827
Deferred income taxes	5,629	9,211
Long-term marketable securities	37,222	16,823
Other assets	2,047	2,872
Total assets	577,877	552,176
Current liabilities:
Accounts payable	8,679	10,161
Accrued compensation	32,327	31,585
Accrued other	7,070	8,256
Income taxes payable	705	114
Deferred revenue	102,010	95,055
Total current liabilities	150,791	145,171
Other long-term liabilities	2,415	2,249
Deferred tax liability	991	941
Accrued long-term retirement benefits	1,578	1,757
Long-term deferred revenue	22,285	25,907
Contingent liabilities, net of current portion	4,219	4,248
Total liabilities	182,279	180,273
Commitments and contingencies
Preferred stock, $0.001 par value:
5,000,000 shares authorized; no shares issued or outstanding at December 31, 2013 and March 31, 2013	0	0
Common stock, $0.001 par value:
150,000,000 shares authorized; 49,826,807 and 49,007,491 shares issued and 41,326,074 and 41,466,921 shares outstanding at December 31, 2013 and March 31, 2013, respectively	50	49
Additional paid-in capital	267,649	253,202
Accumulated other comprehensive income	2,521	671
Treasury stock at cost, 8,500,733 and 7,540,570 shares at December 31, 2013 and March 31, 2013, respectively	(108,513)	(83,480)
Retained earnings	233,891	201,461
Total stockholders’ equity	395,598	371,903
Total liabilities and stockholders’ equity	$ 577,877	$ 552,176