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Summary of Significant Accounting Policies - Net loss per share (Details) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net Loss per Share
Warrants outstanding (in shares)	39,474	39,474
Anti-dilutive securities	9,199,512	6,869,189	5,207,582
Stock options
Net Loss per Share
Anti-dilutive securities	8,342,429	6,112,948	4,720,772
Unvested restricted stock units
Net Loss per Share
Anti-dilutive securities	817,609	716,767	447,336
Warrants
Net Loss per Share
Anti-dilutive securities	39,474	39,474	39,474
Exchange Warrants
Net Loss per Share
Warrants outstanding (in shares)	2,575,000

X

- Definition

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=124432515&loc=d3e3550-109257

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- Definition

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