Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating expenses:
Research and development expenses		$ 11,100
General and administrative expenses	$ 5,012	16,169
Gain on sale of assets	(2,139)	(4,910)
Total operating expenses	2,873	22,359
Loss from continuing operations	(2,873)	(22,359)
Other income and expenses:
Interest income	50	777
Interest expense		(1,528)
Other income (expense), net	(191)	370
Total other income and expenses	(141)	(381)
Net loss from continuing operations before income tax benefit	(3,014)	(22,740)
Income tax benefit (expense)	(14)	1,473
Net loss from continuing operations	(3,028)	(21,267)
Discontinued operations:
Income from discontinued operations, net of tax		3,935
Net loss	(3,028)	(17,332)
Other comprehensive loss:
Unrealized gain on marketable securities		9
Other comprehensive loss		9
Comprehensive loss	$ (3,028)	$ (17,323)
Basic and dilutive net loss per common share
Net loss from continuing operations	$ (0.23)	$ (1.59)
Net income from discontinued operations, net of tax		0.29
Net loss per share	$ (0.23)	$ (1.30)
Weighted-average common shares used in per share calculations—basic and diluted	13,380	13,353
Cash dividends paid per common share		$ 2.00