CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 258,743	$ 109,924
Restricted cash	922	862
Short-term investments	292,314	466,186
Accounts receivable, net	133,922	171,359
Prepaid expenses and other current assets	32,511	30,068
Total current assets	718,412	778,399
Property and equipment, net	54,832	51,919
Right-of-use assets	87,743	0
Deposits and other assets	8,374	8,134
Deferred tax assets, net	18,983	17,316
Total assets	888,344	855,768
Current liabilities:
Accounts payable, accrued expenses, and operating lease liabilities	37,227	33,684
Accrued compensation and employee benefits	36,713	48,045
Deferred revenue and advance payments	190,070	176,540
Total current liabilities	264,010	258,269
Deferred revenue and advance payments	4,539	6,469
Operating lease liabilities	106,661	0
Other long-term liabilities	34,793	61,262
Deferred tax liabilities	35	37
Total liabilities	410,038	326,037
Commitments and Contingencies
Stockholders' Equity
Preferred stock undesignated, $0.001 par value; 5,000 shares authorized; no shares issued or outstanding	0	0
Additional paid-in capital	581,429	576,957
Treasury stock, at cost; 7,648 shares and 7,285 shares, respectively	(634,405)	(586,161)
Accumulated other comprehensive loss	(9,964)	(10,217)
Retained earnings	541,228	549,134
Total stockholders' equity	478,306	529,731
Total liabilities and stockholders' equity	888,344	855,768
Class A
Stockholders' Equity
Common stock	16	16
Total stockholders' equity	16	16
Class B Convertible
Stockholders' Equity
Common stock	2	2
Total stockholders' equity	$ 2	$ 2