UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 116,411	$ 171,899
Marketable securities	235,437	293,269
Total cash, cash equivalents, and marketable securities	351,848	465,168
Accounts receivable	143,445	215,827
Unbilled receivables	239,774	207,155
Other current assets	93,819	88,760
Total current assets	828,886	976,910
Unbilled receivables	132,147	113,278
Goodwill	81,954	79,231
Other long-term assets	512,410	434,843
Total assets	1,555,397	1,604,262
Current liabilities:
Accounts payable	25,604	24,028
Accrued expenses	46,583	59,261
Accrued compensation and related expenses	86,018	123,012
Deferred revenue	229,103	232,865
Other current liabilities	13,118	20,969
Total current liabilities	400,426	460,135
Convertible senior notes, net	589,769	518,203
Operating lease liabilities	87,088	59,053
Other long-term liabilities	18,482	24,699
Total liabilities	1,095,765	1,062,090
Stockholders’ equity:
Preferred stock, 1,000 shares authorized; none issued	0	0
Common stock, 200,000 shares authorized; 81,670 and 80,890 shares issued and outstanding at September 30, 2021 and December 31, 2020, respectively	817	809
Additional paid-in capital	148,098	204,432
Retained earnings	316,150	339,879
Accumulated other comprehensive (loss)	(5,433)	(2,948)
Total stockholders’ equity	459,632	542,172
Total liabilities and stockholders’ equity	$ 1,555,397	$ 1,604,262