Research Funding	6 Months Ended
Jun. 30, 2020
Research and Development [Abstract]
Research Funding	Research FundingCalifornia Institute of Regenerative Medicine Grant AwardIn February 2017, the California Institute for Regenerative Medicine ("CIRM") awarded the Company funds of up to $12.2 million to support the T-Rex Study. The funding is based upon the achievement of certain milestones related to the proportion of subjects enrolled in California, as well as manufacturing and development costs incurred in California. Based on the actual number of subjects enrolled in California, the total amount of funding was revised to $8.1 million. The Company received $5.7 million in initial funding in May 2017, a $1.9 million milestone payment in December 2017, a $0.3 million progress payment in March 2018, and a $200,000 progress payment in May 2019, of which the total will be amortized over the estimated award period through July 2020 as a reduction to the related research and development expenses. As of June 30, 2020, $0.2 million of the funding received was recorded in accrued liabilities. During the three and six months ended June 30, 2020, the Company amortized and recognized $0.7 million and $1.4 million in credits, respectively, to research and development related to CIRM funds received. During the three and six months ended June 30, 2019, the Company amortized and recognized $0.7 million and $1.3 million in credits, respectively, to research and development related to CIRM funds received.

The entire disclosure for research, development, and computer software activities, including contracts and arrangements to be performed for others and with federal government. Includes costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility and in-process research and development acquired in a business combination consummated during the period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 985
-SubTopic 730
-URI http://asc.fasb.org/subtopic&trid=2197926

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