Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income (loss)	$ 218,698	$ (84,813)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	31,304	26,567
Stock-based compensation expense	133,479	95,348
Amortization of right-of-use assets	21,588	22,422
Amortization of content assets	56,580	17,131
Provision for (recoveries of) doubtful accounts	(1,480)	3,097
Other items, net	(298)	345
Changes in operating assets and liabilities:
Accounts receivable	(64,710)	(62,767)
Inventories	(22,050)	(12,895)
Prepaid expenses and other current assets	(63,402)	(3,595)
Other non-current assets	(78,549)	842
Accounts payable	15,139	15,996
Accrued liabilities	34,204	55,279
Operating lease liabilities	(14,465)	18,116
Other long-term liabilities	201	(833)
Deferred revenue	(12,731)	10,907
Net cash provided by operating activities	253,508	101,147
Cash flows from investing activities:
Purchases of property and equipment	(28,020)	(76,012)
Acquisitions of businesses, net of cash acquired	(136,778)
Proceeds from escrows associated with acquisition		1,058
Net cash used in investing activities	(164,798)	(74,954)
Cash flows from financing activities:
Proceeds from equity issued under at-the-market offerings, net of issuance costs	989,615	497,242
Proceeds from borrowings, net of issuance costs		69,325
Repayments of borrowings	(3,750)	(73,075)
Proceeds from equity issued under incentive plans	13,433	11,206
Net cash provided by financing activities	999,298	504,698
Net increase in cash, cash equivalents and restricted cash	1,088,008	530,891
Cash, cash equivalents and restricted cash —beginning of period	1,093,249	517,333
Cash, cash equivalents and restricted cash —end of period	2,181,257	1,048,224
Cash, cash equivalents and restricted cash at end of period:
Cash and cash equivalents	2,179,745	1,047,478
Restricted cash, current		746
Restricted cash, non-current	1,512
Cash, cash equivalents and restricted cash —end of period	2,181,257	1,048,224
Supplemental disclosures of cash flow information:
Cash paid for interest	1,932	2,798
Cash paid for income taxes	956	624
Supplemental disclosures of noncash investing and financing activities:
Non-cash consideration for business combination	15,200
Services to be received as part of a business combination	6,300
Unpaid portion of property and equipment purchases	3,310	4,966
Unpaid portion of acquisition-related expenses	$ 43
Unpaid portion of at-the-market issuance costs		$ 11