CONDENSED CONSOLIDATED BALANCE SHEETS (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 123,731	$ 77,525
Marketable securities	57,124	45,460
Total cash, cash equivalents, and marketable securities	180,855	122,985
Trade accounts receivable, net of allowance of $1,134 and $963	70,513	134,066
Deferred income taxes	10,252	10,202
Income taxes receivable	4,774	6,261
Other current assets	5,735	5,496
Total current assets	272,129	279,010
Property and equipment, net	29,747	30,827
Long-term deferred income taxes	49,163	49,292
Long-term other assets	1,618	1,680
Intangible assets, net	55,455	58,232
Goodwill	20,451	20,451
Total assets	428,563	439,492
Current liabilities:
Accounts payable	2,233	3,330
Accrued expenses	15,267	15,534
Accrued compensation and related expenses	18,848	40,715
Deferred revenue	104,608	95,546
Total current liabilities	140,956	155,125
Income taxes payable	13,707	13,551
Long-term deferred revenue	16,029	18,719
Other long-term liabilities	16,482	15,618
Total liabilities	187,174	203,013
Commitments and contingencies
Stockholders' equity:
Preferred stock, 1,000 shares authorized; no shares issued and outstanding
Common stock, 100,000 shares authorized; 37,951 shares and 37,945 shares issued and outstanding	380	379
Additional paid-in capital	137,591	138,576
Retained earnings	102,276	94,349
Accumulated other comprehensive income	1,142	3,175
Total stockholders' equity	241,389	236,479
Total liabilities and stockholders' equity	$ 428,563	$ 439,492