CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 392,335	$ 547,850	[1]
Short-term marketable securities	422,283	273,366	[1]
Accounts receivable (net of allowance for doubtful accounts of $10,135 and $8,602 at March 31, 2018 and December 31, 2017, respectively)	75,533	76,173	[1]
Prepaid expenses and other current assets	19,975	15,700	[1]
Total current assets	910,126	913,089	[1]
Long-term marketable securities	14,898	25,032	[1]
Property, equipment and software, net	107,889	103,651	[1]
Goodwill	109,420	107,954	[1]
Intangibles, net	16,009	16,893	[1]
Restricted cash	18,800	18,554
Other non-current assets	41,357	40,428	[1]
Total assets	1,218,499	1,225,601	[1]
Current liabilities
Accounts payable	6,620	9,033	[1]
Accrued liabilities	83,413	73,665	[1]
Deferred revenue	3,474	3,469	[1]
Total current liabilities	93,507	86,167	[1]
Long-term liabilities	32,839	30,737	[1]
Total liabilities	126,346	116,904	[1]
Commitments and contingencies			[1]
Stockholders' equity
Common stock, $0.000001 par value, 200,000,000 shares authorized – 83,956,890 shares issued and 83,596,510 shares outstanding at March 31, 2018 and 83,724,916 shares issued and outstanding at December 31, 2017	0	0	[1]
Additional paid-in capital	1,059,168	1,038,017	[1]
Treasury stock	(15,000)	(46)	[1]
Accumulated other comprehensive loss	(6,845)	(8,444)	[1]
Retained earnings	54,830	79,170	[1]
Total stockholders' equity	1,092,153	1,108,697	[1]
Total liabilities and stockholders' equity	$ 1,218,499	$ 1,225,601	[1]

[1] As of January 1, 2018, the Company adopted Accounting Standards Update 2014-09, "Revenue from Contracts with Customers (Topic 606)" ("ASC 606"), using the full retrospective method. Accordingly, the Company has recast certain amounts in prior periods presented. See Note 1 below for additional discussion.