Unaudited Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenue	$ 12,739	$ 21,879	$ 41,035	$ 99,827
Costs and expenses:
Operating expenses (excluding depreciation and amortization)	29,466	23,622	63,939	105,711
Corporate general and administrative	2,679	5,685	12,568	19,020
Depreciation and amortization	518	2,058	3,177	6,437
Research and development	1,480	2,297	5,673	6,658
(Gain) loss on disposal of long-lived assets	(37)	3	(92)	1,096
Impairment of goodwill	11,706	0	11,706	0
Impairment of fixed and long-lived assets	12,521	0	69,975	0
Total costs and expenses	58,333	33,665	166,946	138,922
Loss from operations	(45,594)	(11,786)	(125,911)	(39,095)
Other (expense) income:
Gain on lease termination	0	0	576	0
Interest expense	(19)	(1)	(40)	(2,014)
Other income, net	291	436	322	1,238
Total other income (expense), net	272	435	858	(776)
Loss before income taxes	(45,322)	(11,351)	(125,053)	(39,871)
Income tax benefit	81	191	6,282	694
Loss from continuing operations	(45,241)	(11,160)	(118,771)	(39,177)
Income from discontinued operations, net of tax	0	117	0	44,583
Net (loss) income	$ (45,241)	$ (11,043)	$ (118,771)	$ 5,406
Basic earnings (loss) per common share:
Continuing operations (in dollars per share)	$ (0.66)	$ (0.19)	$ (1.75)	$ (0.67)
Discontinued operations, net of tax (in dollars per share)	0	0	0	0.76
Basic earnings (loss) per common share (in dollars per share)	(0.66)	(0.19)	(1.75)	0.09
Diluted earnings (loss) per common share:
Continuing operations (in dollars per share)	(0.66)	(0.19)	(1.75)	(0.67)
Discontinued operations, net of tax (in dollars per share)	0	0	0	0.76
Diluted earnings (loss) per common share (in dollars per share)	$ (0.66)	$ (0.19)	$ (1.75)	$ 0.09
Weighted average common shares:
Weighted average common shares used in computing basic earnings (loss) per common share (in shares)	68,217	58,608	68,063	58,491
Weighted average common shares used in computing diluted earnings (loss) per common share (in shares)	68,217	58,608	68,063	58,491