CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 97,278	$ 114,585
Marketable securities	126,738	96,631
Total cash, cash equivalents, and marketable securities	224,016	211,216
Trade accounts receivable, net of allowance of $2,100 and $1,540	129,252	154,844
Deferred income taxes	12,903	12,974
Income taxes receivable	14,688	4,502
Other current assets	12,310	9,544
Total current assets	393,169	393,080
Property and equipment, net	31,830	30,156
Long-term deferred income taxes	71,998	69,258
Long-term other assets	3,715	2,783
Intangible assets, net	36,412	45,664
Goodwill	46,816	46,860
Total assets	583,940	587,801
Current liabilities:
Accounts payable	7,617	4,752
Accrued expenses	39,049	42,958
Accrued compensation and related expenses	43,386	47,250
Deferred revenue	134,075	134,672
Total current liabilities	224,127	229,632
Income taxes payable	24,562	24,896
Long-term deferred revenue	13,857	20,859
Other long-term liabilities	16,348	17,709
Total liabilities	$ 278,894	$ 293,096
Stockholders' equity:
Preferred stock, 1,000 shares authorized; no shares issued and outstanding
Common stock, 200,000 shares authorized; 76,465 shares and 76,357 shares issued and outstanding	$ 765	$ 764
Additional paid-in capital	145,466	141,495
Retained earnings	161,522	153,058
Accumulated other comprehensive loss	(2,707)	(612)
Total stockholders' equity	305,046	294,705
Total liabilities and stockholders' equity	$ 583,940	$ 587,801