Net Loss Per Share - Antidilutive Securities (Details) - shares	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Employee stock options
Net Loss Per Share
Potentially dilutive securities	1,480,139	437,603
Restricted stock subject to forfeiture and restricted stock units
Net Loss Per Share
Potentially dilutive securities	241,828	183,796
Common stock warrants
Net Loss Per Share
Potentially dilutive securities	758,939	1,290,103

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.

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=6371337&loc=d3e3550-109257

Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration