UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 92,104	$ 114,422
Marketable securities	20,465	93,001
Total cash, cash equivalents, and marketable securities	112,569	207,423
Accounts receivable	123,268	180,872
Unbilled receivables	172,090	172,656
Other current assets	58,204	49,684
Total current assets	466,131	610,635
Long-term unbilled receivables	123,962	151,237
Goodwill	78,862	72,858
Other long-term assets	248,069	147,823
Total assets	917,024	982,553
Current liabilities:
Accounts payable	15,435	16,487
Accrued expenses	41,520	45,506
Accrued compensation and related expenses	88,349	84,671
Deferred revenue	159,849	185,145
Other current liabilities	15,742	0
Total current liabilities	320,895	331,809
Operating lease liabilities	56,904	0
Other long-term liabilities	10,393	29,213
Total liabilities	388,192	361,022
Stockholders’ equity:
Preferred stock, 1,000 shares authorized; none issued	0	0
Common stock, 200,000 shares authorized; 79,324 and 78,526 shares issued and outstanding at September 30, 2019 and December 31, 2018, respectively	793	785
Additional paid-in capital	129,559	123,205
Retained earnings	412,389	510,863
Accumulated other comprehensive (loss)	(13,909)	(13,322)
Total stockholders’ equity	528,832	621,531
Total liabilities and stockholders’ equity	$ 917,024	$ 982,553