Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Mar. 31, 2012
Current assets:
Cash and cash equivalents	$ 90,836	$ 117,255
Marketable securities	35,324	79,617
Accounts receivable, net of allowance for doubtful accounts of $1,033 and $226 at December 31, 2012 and March 31, 2012, respectively	61,908	69,795
Inventories	7,427	8,021
Prepaid income taxes	8,917	4,600
Deferred income taxes	5,664	4,237
Prepaid expenses and other current assets	9,465	6,162
Total current assets	219,541	289,687
Fixed assets, net	18,077	16,457
Goodwill	203,251	170,384
Intangible assets, net	65,433	54,685
Deferred income taxes	11,755	17,892
Long-term marketable securities	10,540	16,644
Other assets	3,523	2,008
Total assets	532,120	567,757
Current liabilities:
Accounts payable	9,151	7,539
Accrued compensation	29,016	23,050
Accrued other	7,404	6,235
Current portion of contingent liabilities	4,224	3,774
Deferred revenue	90,567	93,493
Total current liabilities	140,362	134,091
Other long-term liabilities	2,044	2,347
Deferred tax liability	2,467	1,410
Accrued long-term retirement benefits	1,818	1,990
Long-term deferred revenue	22,717	18,722
Long-term debt	0	62,000
Contingent liabilities, net of current portion	2,370	4,828
Total liabilities	171,778	225,388
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock, $0.001 par value: 5,000,000 shares authorized; no shares issued or outstanding at December 31, 2012 and March 31, 2012	0	0
Common stock, $0.001 par value: 150,000,000 shares authorized; 48,887,013 and 48,185,731 shares issued and 41,604,647 and 41,814,191 shares outstanding at December 31, 2012 and March 31, 2012, respectively	49	48
Additional paid-in capital	248,694	237,289
Accumulated other comprehensive income	1,450	212
Treasury stock at cost, 7,282,366 and 6,371,540 shares at December 31, 2012 and March 31, 2012, respectively	(76,759)	(56,032)
Retained earnings	186,908	160,852
Total stockholders' equity	360,342	342,369
Total liabilities and stockholders' equity	$ 532,120	$ 567,757