CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Operating activities:
Net (loss) income	$ (10,185)	$ 22,188
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	9,342	5,456
Reduction in carrying amount of right-of-use assets	6,134	6,087
Credit losses and sales allowances	1,874	892
Net realized (gain) loss on short-term investments	(94)	41
Deferred taxes	(13,341)	(3,352)
Release of liabilities for unrecognized tax benefits	0	(1,077)
Share-based compensation expense	7,897	7,887
Digital asset impairment losses	44,242	0
Changes in operating assets and liabilities:
Accounts receivable	6,439	11,781
Prepaid expenses and other current assets	391	4,513
Deposits and other assets	(175)	349
Accounts payable and accrued expenses	902	(11,618)
Accrued compensation and employee benefits	(7,221)	(7,368)
Deferred revenue and advance payments	(12,385)	23,612
Operating lease liabilities	(7,148)	(6,394)
Other long-term liabilities	1,625	(674)
Net cash provided by operating activities	28,297	52,323
Investing activities:
Purchases of digital assets	(425,000)	0
Proceeds from redemption of short-term investments	119,886	589,357
Purchases of property and equipment	(1,162)	(9,382)
Purchases of short-term investments	(9,928)	(320,487)
Net cash (used in) provided by investing activities	(316,204)	259,488
Financing activities:
Proceeds from sale of class A common stock under exercise of employee stock options	3,616	5,442
Purchases of treasury stock	(122,480)	(48,244)
Net cash used in financing activities	(118,864)	(42,802)
Effect of foreign exchange rate changes on cash, cash equivalents, and restricted cash	2,839	(3,926)
Net (decrease) increase in cash, cash equivalents, and restricted cash	(403,932)	265,083
Cash, cash equivalents, and restricted cash, beginning of period	457,816	110,786
Cash, cash equivalents, and restricted cash, end of period	$ 53,884	$ 375,869