Goodwill and Intangible Assets, Net - Schedule of Goodwill and Intangible Assets Net (Details) - USD ($) $ in Thousands		Jun. 30, 2024	Dec. 31, 2023
Finite-Lived Intangible Assets [Line Items]
Goodwill	[1]	$ 10,672	$ 10,672
Total intangible assets		66,143	66,143
Accumulated amortization	[2]	(19,603)	(19,581)
Intangible assets, net		46,540	46,562
IPR&D - OPC1 [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	[3]	31,700	31,700
IPR&D - VAC2 [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets	[3]	14,840	14,840
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization		18,953	18,953
Royalty Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets subject to amortization	[4]	$ 650	$ 650

[1] Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired and liabilities assumed in the Asterias Merger, see Note 13 (Commitments and Contingencies) for further discussion on the Asterias Merger. To date, we have not recognized any goodwill impairment.

[2] The acquired patents and acquired royalty contracts were fully amortized as of the end of the first quarter of 2024.

[3] Asterias had two in-process research and development ("IPR&D") intangible assets that were valued at $46.5 million as part of the purchase price allocation that was performed in connection with the Asterias Merger. The fair value of these assets at the acquisition date consisted of $31.7 million pertaining to the OPC1 program and $14.8 million pertaining to the VAC platform.

[4] Asterias had royalty cash flows under patent families it acquired from Geron Corporation. Such patent families are expected to continue to generate revenue, are not used in the OPC1 or the VAC platform, and are considered to be separate long-lived intangible assets under ASC Topic 805, Business Combinations