CIRM Grants (Details) $ in Millions					12 Months Ended
	Apr. 05, 2022 USD ($)	Apr. 30, 2021 USD ($)	Jan. 31, 2021 USD ($)	Jan. 04, 2021 USD ($)	Dec. 31, 2019 USD ($) Grant	Mar. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)	Nov. 12, 2020 USD ($)	Apr. 30, 2019 USD ($)
LAD-1 CIRM Grant [Member]
CIRM Grants [Abstract]
Grant award for clinical development support									$ 7.5
Number of grants | Grant					2
Amount received from grant for eligible costs incurred					$ 1.2
Grant receivable included in prepaid and other assets						$ 0.9	$ 1.1
Milestone payments received		$ 1.0	$ 1.1
LAD-1 CIRM Grant [Member] | Subsequent Event [Member]
CIRM Grants [Abstract]
Milestone payments received	$ 0.9
IMO CIRM Grant [Member]
CIRM Grants [Abstract]
Grant award for clinical development support								$ 3.7
Amount received from grant for eligible costs incurred				$ 1.0