ELAD Sales Agreement - Estimated Fair Value of ELAD Assets (Details) - ELAD-Related Assets - Disposal Group, Disposed of by Sale, Not Discontinued Operations $ in Thousands	Sep. 30, 2020 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of ELAD Assets	$ 2,070
Clinical development equipment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of ELAD Assets	306
Supplies and working cell banks
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of ELAD Assets	1,000
In process research & development (“IPR&D”)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated fair value of ELAD Assets	$ 764