UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands		Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	[1]	$ 144,291	$ 162,279
Marketable securities	[1]	99,292	61,469
Total cash, cash equivalents, and marketable securities	[1]	243,583	223,748
Accounts receivable	[1]	141,384	222,735
Unbilled receivables	[1]	151,354	158,898
Other current assets	[1]	63,864	41,135
Total current assets	[1]	600,185	646,516
Long-term unbilled receivables	[1]	169,330	160,708
Goodwill	[1]	72,911	72,952
Other long-term assets	[1]	130,614	131,391
Total assets	[1]	973,040	1,011,567
Current liabilities:
Accounts payable	[1]	14,411	17,370
Accrued expenses	[1]	44,882	45,508
Accrued compensation and related expenses	[1]	48,691	66,040
Deferred revenue	[1]	163,525	166,297
Total current liabilities	[1]	271,509	295,215
Deferred income tax liabilities	[1]	38,208	38,463
Other long-term liabilities	[1]	24,151	23,652
Total liabilities	[1]	333,868	357,330
Stockholders' equity:
Preferred stock, 1,000 shares authorized; no shares issued and outstanding	[1]
Common stock, 200,000 shares authorized; 78,748 and 78,081 shares issued and outstanding at June 30, 2018 and December 31, 2017, respectively	[1]	787	781
Additional paid-in capital	[1]	141,400	152,097
Retained earnings	[1]	506,769	508,051
Accumulated other comprehensive loss	[1]	(9,784)	(6,692)
Total stockholders' equity	[1]	639,172	654,237
Total liabilities and stockholders' equity	[1]	$ 973,040	$ 1,011,567

[1] On January 1, 2018 the Company adopted the ASC 606 revenue recognition standard and has adjusted prior periods to conform. See Note 2. "New Accounting Pronouncements" for additional information.