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Stock-Based Compensation and Warrants - Stock incentive plan and other information (Details) - USD ($)		1 Months Ended		12 Months Ended
	Nov. 18, 2016	Sep. 30, 2021	Mar. 20, 2007	Dec. 31, 2021	Dec. 31, 2020	Nov. 16, 2020	Sep. 17, 2020	Dec. 31, 2019	Oct. 15, 2018	Dec. 26, 2017	Nov. 08, 2016	Nov. 02, 2010
Share-based Compensation Arrangement by Share-based Payment Award
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options				$ 771,000
Proceeds from Stock Options Exercised				0	$ 0
Exercise price per warrant						$ 1.38			$ 1.38
Warrants Not Settleable in Cash, Fair Value Disclosure										$ 9,000
IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Stock Issued During Period, Shares, New Issues	714,286
Class of Warrant or Right, Number of Securities Called by Warrants or Rights											1,428,571
Shares Issued, Price Per Share	$ 35.00
Warrants Not Settleable in Cash, Fair Value Disclosure						$ 15,700,000		$ 100,000,000
Series B Warrants [Member] \| IPO [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Exercise price per warrant	$ 60.20
General and Administrative Expenses and Research and Development Expense [Member] \| Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense				$ 204,000	$ 213,000
Employees And Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross				2,260,000	1,540,000
Consultant [Member] \| General and Administrative Expenses and Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense				$ 212,000	$ 137,000
Employees \| General and Administrative Expenses and Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Allocated Share-based Compensation Expense				$ 500,000	$ 400,000
2007 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number			71,429	5,145
2007 Stock Plan [Member] \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			7,143
2010 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				3,800,000								85,714
Share-based Compensation Arrangement by Share-based Payment Award, Number of shares authorized		4,000,000,000,000
2010 Stock Plan [Member] \| Board of Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				2,450,130
2020 Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number							4,000,000