Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues
Revenues	$ 84	$ 4,262	$ 84	$ 5,707
Costs and expenses
Research and development	13,767	11,139	25,862	22,554
General and administrative	4,432	2,867	7,906	5,973
Depreciation	222	157	412	341
Total costs and expenses	18,421	14,163	34,180	28,868
Loss from operations	(18,337)	(9,901)	(34,096)	(23,161)
Other income (expense), net	(35)	213	80	517
Net loss and comprehensive loss	$ (18,372)	$ (9,688)	$ (34,016)	$ (22,644)
Net loss per share, basic and diluted (in dollars per share)	$ (0.10)	$ (0.06)	$ (0.19)	$ (0.15)
Weighted average shares outstanding, basic and diluted (in shares)	191,317	150,163	177,016	148,075
Grant revenue
Revenues
Revenues	$ 7	$ 69	$ 7	$ 73
Healios \| Contract revenue
Revenues
Revenues	$ 77	$ 4,193	$ 77	$ 5,634

The amount of costs and expenses before other expenses.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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The net result for the period of deducting operating expenses from operating revenues.

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The aggregate 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 costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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