UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE LOSS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Revenues	$ 16,083	$ 4,000	$ 46,028	$ 11,529
Costs and operating expenses:
Cost of revenues, excluding depreciation and amortization	12,334	2,279	33,024	5,315
Product development	3,139	705	9,316	2,237
Sales and marketing	2,297	692	8,329	2,205
General and administrative	8,190	6,711	24,489	10,794
Restructuring charges and acquisition costs	10	1,995	3,442	2,074
Depreciation and amortization	3,389	999	9,132	2,958
Total costs and operating expenses	29,359	13,381	87,732	25,583
Operating loss	(13,276)	(9,381)	(41,704)	(14,054)
Nonoperating expense (income), net	12,237	150	14,797	(1,620)
Loss before income taxes	(25,513)	(9,531)	(56,501)	(12,434)
Income tax expense (benefit)	(394)	20	(758)	38
Net loss	(25,119)	(9,551)	(55,743)	(12,472)
Other comprehensive loss:
Foreign currency translation loss	(5,487)	(37)	(6,805)	(207)
Comprehensive loss	$ (30,606)	$ (9,588)	$ (62,548)	$ (12,679)
Net loss per share - basic (in dollars per share)	$ (0.22)	$ (0.16)	$ (0.51)	$ (0.23)
Net loss per share - diluted (in dollars per share)	$ (0.22)	$ (0.16)	$ (0.51)	$ (0.23)
Weighted-average shares outstanding during the period – basic (in shares)	113,579,298	59,314,867	109,443,353	54,275,784
Weighted-average shares outstanding during the period – diluted (in shares)	113,579,298	59,314,867	109,443,353	54,275,784