CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 98,787	$ 98,107
Costs and expenses:
Cost of revenues	61,111	56,823
Sales and marketing	25,034	25,523
Research and development	10,593	10,370
General and administrative	15,090	13,623
Change in fair value of contingent consideration	460	3,062
Total costs and expenses	112,288	109,401
Loss from operations	(13,501)	(11,294)
Interest expense	(3,574)	(3,439)
Other income (expense), net	580	1,531
Loss before income taxes	(16,495)	(13,202)
Provision for income taxes	230	26
Net loss	$ (16,725)	$ (13,228)
Net loss per share, basic and diluted	$ (0.19)	$ (0.14)
Weighted-average number of common shares used in computing net loss per share, basic and diluted	89,638	94,263