Nature of Business - Reverse Stock Split (Details) - Histogenics	3 Months Ended
Mar. 31, 2020 $ / shares
Nature of Business
Reverse stock split ratio	0.0167
Shares issued exchange rate to former Ocugen's stockholders (in USD per share)	$ 0.4794

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

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