CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 68,363	$ 114,422
Marketable securities	0	93,001
Total cash, cash equivalents, and marketable securities	68,363	207,423
Accounts receivable	199,720	180,872
Unbilled receivables	180,219	172,656
Other current assets	57,308	49,684
Total current assets	505,610	610,635
Long-term unbilled receivables	121,736	151,237
Goodwill	79,039	72,858
Other long-term assets	278,427	147,823
Total assets	984,812	982,553
Current liabilities:
Accounts payable	17,475	16,487
Accrued expenses	48,001	43,143
Accrued compensation and related expenses	104,126	84,671
Deferred revenue	190,080	185,145
Other current liabilities	18,273	2,363
Total current liabilities	377,955	331,809
Operating lease liabilities	52,610	0
Other long-term liabilities	15,237	29,213
Total liabilities	445,802	361,022
Commitments and Contingencies
Stockholders’ equity:
Preferred stock, $0.01 par value, 1,000 shares authorized; none issued	0	0
Common stock, $0.01 par value, 200,000 shares authorized; 79,599 and 78,526 shares issued and outstanding at December 31, 2019 and 2018, respectively	796	785
Additional paid-in capital	140,523	123,205
Retained earnings	410,919	510,863
Accumulated other comprehensive (loss)
Net unrealized gain on available-for-sale marketable securities, net of tax	0	(249)
Foreign currency translation adjustments	(13,228)	(13,073)
Total stockholders’ equity	539,010	621,531
Total liabilities and stockholders’ equity	$ 984,812	$ 982,553