Nature of Business - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended		3 Months Ended	6 Months Ended
	Jul. 08, 2022	May 03, 2022	Jan. 28, 2022	Jul. 16, 2021	Aug. 31, 2022	Mar. 31, 2022	Mar. 31, 2022	Jun. 30, 2022	Jun. 30, 2021	Aug. 04, 2022	May 09, 2022	May 05, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Accumulated deficit								$ (266,700)					$ (246,452)
Cash and cash equivalents								$ 6,589					$ 29,988
Directors' & Officers' run off insurance amount						$ 6,800
Restructuring charges, number of workforce headcount reduction percentage						40.00%
Preferred stock issued								2,872					0
Preferred stock par value								$ 0.001					$ 0.001
Exercise price of warrants								$ 0.51					1.26
Net proceeds after deducting estimated offering costs								$ 3,944	$ 13,464
Common stock, par value								$ 0.001					$ 0.001
Loan and Security Agreement | Pontifax
Class of Stock [Line Items]
Voluntary principal repayments					$ 500		$ 5,000
Outstanding principal balance						$ 5,000	$ 5,000	$ 4,500					$ 10,000
Retention Plan
Class of Stock [Line Items]
Retention agreement received salary adjustment percentage			6.50%
RSUs granted			2,998,500
Employees retention payment			$ 3,000
Percentage of amount employee to repay for resigns or terminated			50.00%
Securities Purchase Agreement
Class of Stock [Line Items]
Preferred stock issued		2,872.1376
Preferred stock par value		$ 1,000
Net proceeds from issuance of preferred stock		$ 2,300
Conversion price		$ 16.00
Securities Purchase Agreement | Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock par value		$ 0.001
Conversion of preferred stock		8,975,430										8,975,430
Securities Purchase Agreement | Series E Preferred Stock
Class of Stock [Line Items]
Preferred stock par value		$ 0.001
Conversion of preferred stock		8,975,430									8,975,430
Conversion price		$ 0.16
At Market Issuance Sales Agreement
Class of Stock [Line Items]
Common stock shares issued and sold				4,081,338
At Market Issuance Sales Agreement | Updated B. Riley ATM Agreement.
Class of Stock [Line Items]
Common stock shares issued and sold							6,804,888
Weighted average price of common stock shares sold and issued							$ 0.62
Net proceeds after deducting estimated offering costs							$ 3,900
HCW Warrants
Class of Stock [Line Items]
Warrant issued		1,256,561
Exercise price of warrants		$ 0.20
Warrant term		5 years
2022 Common Warrants
Class of Stock [Line Items]
Warrant issued		22,438,575
Exercise price of warrants		$ 0.1694
Warrant term		5 years
Subsequent Event
Class of Stock [Line Items]
Common stock, par value										$ 0.001
Subsequent Event | HCW ATM Agreement
Class of Stock [Line Items]
Common stock shares issued and sold	14,358,057
Weighted average price of common stock shares sold and issued	$ 0.14
Net proceeds after deducting estimated offering costs	$ 1,900