Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Mar. 31, 2011
Assets
Cash and cash equivalents	$ 102,762	$ 67,168
Marketable securities	61,167	133,430
Accounts receivable, net of allowance for doubtful accounts of $259 and $346 at December 31, 2011 and March 31, 2011, respectively	49,593	62,801
Inventories	9,414	8,925
Prepaid income taxes	4,413	3,205
Deferred income taxes	3,624	3,383
Prepaid expenses and other current assets	5,692	4,814
Total current assets	236,665	283,726
Fixed assets, net	15,213	13,467
Goodwill	169,952	128,177
Intangible assets, net	56,390	47,686
Deferred income taxes	21,849	25,167
Long-term marketable securities	28,360	27,880
Other assets	2,463	1,467
Total assets	530,892	527,570
Liabilities and Stockholders' Equity
Accounts payable	6,585	9,709
Accrued compensation	20,763	21,854
Accrued other	6,932	4,786
Current portion of long-term debt	0	15,000
Current portion of contingent liabilities	3,014	0
Deferred revenue	82,802	85,241
Total current liabilities	120,096	136,590
Other long-term liabilities	2,170	1,721
Deferred tax liability	1,590	0
Accrued long-term retirement benefits	2,044	1,859
Long-term deferred revenue	12,311	14,735
Long-term debt, net of current portion	62,000	53,106
Contingent liabilities, net of current portion	4,986	0
Total liabilities	205,197	208,011
Commitments and contingencies (Note 13)
Stockholders' equity:
Preferred stock, $0.001 par value: 5,000,000 shares authorized; no shares issued or outstanding at December 31, 2011 and March 31, 2011	0	0
Common stock, $0.001 par value: 150,000,000 shares authorized; 47,778,373 and 47,441,879 shares issued and 41,534,672 and 42,557,221 shares outstanding at December 31, 2011 and March 31, 2011, respectively	48	47
Additional paid-in capital	232,969	227,201
Accumulated other comprehensive loss	(1,851)	(676)
Treasury stock at cost, 6,243,701 and 4,884,658 shares at December 31, 2011 and March 31, 2011, respectively	(53,376)	(35,437)
Retained earnings	147,905	128,424
Total stockholders' equity	325,695	319,559
Total liabilities and stockholders' equity	$ 530,892	$ 527,570