Condensed Unaudited Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Income Statement [Abstract]
Revenues	$ 115,133	$ 95,284	$ 323,492	$ 253,674
Operating expenses:
Cost of revenues (excluding depreciation and amortization)	44,525	40,705	125,709	100,530
General and administrative expenses	50,643	17,150	135,682	53,270
Selling and marketing expenses	60,537	18,269	163,952	54,359
Research and development expenses	13,998	6,905	50,285	23,789
Depreciation and amortization	11,783	10,133	33,135	30,171
Acquisition related expenses	480	1,230	1,516	4,321
Restructuring expenses	30	259	467	1,950
Total operating expenses	181,996	94,651	510,746	268,390
Loss from operations	(66,863)	633	(187,254)	(14,716)
Interest expense	1,342	3,823	5,705	12,548
Other (incomes) / expenses, net	496	(188)	1,031	(546)
Gain on extinguishment of debt	0		(10,000)
Change in fair value of warrants and derivative liabilities	0	9,700	5,000	16,400
Total other (incomes) / expenses	1,838	13,335	1,736	28,402
Loss before income taxes	(68,701)	(12,702)	(188,990)	(43,118)
Income tax provision / (benefit)	428	301	(565)	1,319
Net loss	(69,129)	(13,003)	(188,425)	(44,437)
Other comprehensive (loss) / income :
Foreign currency translation adjustment	(77)	272	(152)	(516)
Total comprehensive loss	(69,206)	(12,731)	(188,577)	(44,953)
Net loss per share
Net loss	(69,129)	(13,003)	(188,425)	(44,437)
Cumulative redeemable convertible preferred stock dividends	0	3,774	7,060	11,150
Net loss available to common stockholders	$ (69,129)	$ (16,777)	$ (195,485)	$ (55,587)
Basic loss per share	$ (0.53)	$ (0.51)	$ (2.60)	$ (1.70)
Diluted loss per share	$ (0.53)	$ (0.51)	$ (2.60)	$ (1.70)
Weighted average number of shares used to compute net loss per share
Basic	129,731,980	32,607,357	75,313,520	32,607,373
Diluted	129,731,980	32,607,357	75,313,520	32,607,373