UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 110,367	$ 114,422
Marketable securities	91,804	93,001
Total cash, cash equivalents, and marketable securities	202,171	207,423
Accounts receivable	135,352	180,872
Unbilled receivables	161,480	172,656
Other current assets	63,731	49,684
Total current assets	562,734	610,635
Long-term unbilled receivables	130,494	151,237
Goodwill	72,898	72,858
Other long-term assets	190,433	147,823
Total assets	956,559	982,553
Current liabilities:
Accounts payable	11,559	16,487
Accrued expenses	40,947	45,506
Accrued compensation and related expenses	56,349	84,671
Deferred revenue	180,845	185,145
Other current liabilities	12,447	0
Total current liabilities	302,147	331,809
Operating lease liabilities	45,325	0
Deferred income tax liabilities	8,319	6,939
Other long-term liabilities	12,339	22,274
Total liabilities	368,130	361,022
Stockholders’ equity:
Preferred stock, 1,000 shares authorized; none issued	0	0
Common stock, 200,000 shares authorized; 78,896 and 78,526 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively	789	785
Additional paid-in capital	119,182	123,205
Retained earnings	479,779	510,863
Accumulated other comprehensive loss	(11,321)	(13,322)
Total stockholders’ equity	588,429	621,531
Total liabilities and stockholders’ equity	$ 956,559	$ 982,553