Warrants - 2019 Bridge Note Warrants (Details)						1 Months Ended							12 Months Ended
	Jan. 08, 2021 shares	Mar. 23, 2020 USD ($) $ / shares	Mar. 05, 2020 USD ($) $ / shares shares	Jul. 23, 2019 USD ($) $ / shares shares	Jun. 26, 2019 USD ($) item	Jan. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares shares	May 31, 2020 USD ($) $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Feb. 29, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Jul. 31, 2019 USD ($) $ / shares Y shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2020 shares	Jul. 21, 2020 shares	Apr. 30, 2020 $ / shares	Mar. 22, 2020 $ / shares	Mar. 04, 2020 $ / shares	Jan. 31, 2020 $ / shares	Dec. 31, 2019 shares	Aug. 31, 2019 $ / shares	May 31, 2019 USD ($)
Debt
Fair value of warrants | $													$ 1,000
Loss on extinguishment of debt | $						$ (753,000)							$ 753,000	$ 1,864,000
Warrants outstanding							2,401,818						563,451	2,401,818							6,473,964
Number of shares issued for preferred stock converted												166
Aggregate purchase price of warrants | $							$ 179,000						$ 1,000	$ 179,000
Series B convertible preferred stock
Debt
Units issued												10,787
Number of shares in exchange for each unit												1
Class A units | Underwritten Public Offering
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right												1
Units issued												962,166
Unit Price | $ / shares												$ 6.00
Number of shares in exchange for each unit												1
Number of warrants converted for each share												1
Class B units
Debt
Units issued												10,787
Issuance costs | $												$ 1,600,000
Class B units | Underwritten Public Offering
Debt
Units issued												10,787
Unit Price | $ / shares												$ 1,000
Class B units | Underwritten Public Offering | Series B convertible preferred stock
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right												166
Number of shares in exchange for each unit												1
Number of warrants converted for each share												166
2019 Bridge Note Warrants
Debt
Debt Instrument, Face Amount | $					$ 5,100,000
Number Of Promissory Notes Issued | item					21
Fair value of warrants | $				$ 4,300,000
Warrants exercisable				927,083
Warrants outstanding							634,370						190,622	634,370
Class of Warrant or Right, Number of Securities Exercisable				927,083
Warrants exercised	135,416												135,416
2019 Bridge Note Warrants | Stock price
Debt
Warrant liability | $ / shares				5.19
2019 Bridge Note Warrants | Strike price
Debt
Warrant liability | $ / shares				6.00
2019 Bridge Note Warrants | Expected life
Debt
Term of warrant				4 years 9 months 18 days
2019 Bridge Note Warrants | Volatility
Debt
Warrant liability				146
2019 Bridge Note Warrants | Risk free rate
Debt
Warrant liability				1.76
Series 1 warrants
Debt
Warrants exercisable										69,340
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right													464,058
Warrants issued											2,760,000	2,760,000
Impact of modification | $											$ 522,000
Warrants outstanding							609,450						145,396	609,450
Impact of modification previously reported | $														$ 6,000
Number of warrants converted for each share													464,058
Term of warrant												5 years
Exercise price (in dollars per share) | $ / shares										$ 2.08	$ 4.20	$ 6.00								$ 6.00		$ 6.00
Proceeds from issuance of warrants | $										$ 144,000			$ 682,000
Class of Warrant or Right, Number of Securities Exercisable										69,340
Series 1 warrants | Class A units
Debt
Common stock issued and issuable												962,166
Warrants issued												962,166
Series 1 warrants | Class A units | Underwritten Public Offering
Debt
Number of shares in exchange for each unit												1
Series 1 warrants | Class B units
Debt
Units issued												10,787
Common stock issued and issuable												1,797,833
Series 1 warrants | Class B units | Underwritten Public Offering
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right												1
Number of shares in exchange for each unit												166
Number of shares issued for preferred stock converted												166
Number of warrants converted for each share												1
Series 2 warrants
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right													475,725
Warrants issued												2,760,000
Issuance of warrants | $												$ 5,000,000.0
Warrants outstanding							609,450						133,730	609,450
Impact of modification previously reported | $			$ 6,000											$ 65,000
Number of warrants converted for each share													475,725
Term of warrant												5 years
Exercise price (in dollars per share) | $ / shares		$ 1.57	$ 1.82						$ 6.00			$ 6.00						$ 6.00	$ 6.00
Proceeds from issuance of warrants | $			$ 55,000										$ 700,000
Net proceeds from issuance of warrants | $		$ 628,000
Issuance costs | $		25,000
Debt Conversion, Converted Instrument, Shares Issued			30,313
Fair Value Adjustment of Warrants | $		$ 65,000
Warrants exercised			30,313												2,760,000
Series 2 warrants | Exercise Agreement
Debt
Exercise price (in dollars per share) | $ / shares									$ 6.00
Proceeds from issuance of warrants | $									$ 653,000
Warrants exercised									416,666
Series 2 warrants | Stock price
Debt
Warrant liability | $ / shares												5.19
Series 2 warrants | Strike price
Debt
Warrant liability | $ / shares												6.00
Series 2 warrants | Expected life
Debt
Warrant Exercisable Period After, Issuance Date												5 years
Warrant liability | Y												5.0
Series 2 warrants | Volatility
Debt
Warrant liability												109
Series 2 warrants | Risk free rate
Debt
Warrant liability												1.83
Series 2 warrants | Series B convertible preferred stock | Exercise Agreement
Debt
Exercise price (in dollars per share) | $ / shares									$ 1.34
Series 2 warrants | Class A units
Debt
Units issued												962,166
Common stock issued and issuable												962,166
Series 2 warrants | Class A units | Underwritten Public Offering
Debt
Number of shares in exchange for each unit												1
Series 2 warrants | Class B units
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right												500
Units issued												10,787
Common stock issued and issuable												1,797,833
Number of warrants converted for each share												500
Series 2 warrants | Class B units | Underwritten Public Offering
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right												2
Number of shares in exchange for each unit												166
Number of shares issued for preferred stock converted												166
Number of warrants converted for each share												2
Series 3 warrants
Debt
Fair value of warrant | $						1,500,000							$ 1,800,000
Warrant Exercise Inducement Offer, Warrants To Purchase Common Stock Exchanged	135,416							1,335,020
Warrants outstanding							71,500						0	71,500
Term of warrant								5 years
Exercise price (in dollars per share) | $ / shares								$ 1.59
Aggregate purchase price of warrants | $								$ 3,700,000
Warrants exercised													206,915			2,818,784
Series 3 warrants | Stock price
Debt
Warrant liability | $ / shares							2.45	0.15						2.45
Series 3 warrants | Strike price
Debt
Warrant liability | $ / shares							0.00	1.32						0.00
Series 3 warrants | Expected life
Debt
Term of warrant							4 years 10 months 20 days	5 years 6 months						4 years 10 months 20 days
Series 3 warrants | Volatility
Debt
Warrant liability							142	141						142
Series 3 warrants | Risk free rate
Debt
Warrant liability							0.36	0.34						0.36
Modification of Certain 2019 Bridge Note Warrants [Member]
Debt
Impact of modification previously reported | $										$ 9,000
Exercise price (in dollars per share) | $ / shares										$ 2.08										$ 6.00
Net proceeds from issuance of warrants | $										$ 173,000
Debt Conversion, Converted Instrument, Shares Issued										83,333
Warrants exercised										83,333
Modification of the 2019 Bridge Note Warrants and Inducement Offer
Debt
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right													443,748
Warrant Exercise Inducement Offer, Warrants To Purchase Common Stock Exchanged								31,250
Warrant Exercise Inducement Offer, Warrants To Purchase Common Stock Issued								31,250
Number of warrants converted for each share													443,748
Exercise price (in dollars per share) | $ / shares								$ 1.47									$ 6.00
Proceeds from issuance of warrants | $													$ 652,000
Fair Value Adjustment of Warrants | $								$ 166,000
May 2020 Modification of the July 2019 Series 1 Warrants and Inducement Offer
Debt
Warrant Exercise Inducement Offer, Warrants To Purchase Common Stock Exchanged								1,524,013
Exercise price (in dollars per share) | $ / shares								$ 1.47									4.20
Fair Value Adjustment of Warrants | $								$ 284,000
May 2020 Modification of the July 2019 Series 2 Warrants and Inducement Offer
Debt
Impact of modification | $								$ 406,000
Warrant Exercise Inducement Offer, Warrants To Purchase Common Stock Exchanged								1,344,520
Exercise price (in dollars per share) | $ / shares								$ 1.47									$ 6.00
Exchange Note 2
Debt
Debt Instrument, Face Amount | $						$ 1,800,000																	$ 2,300,000
Debt Conversion, Converted Instrument, Shares Issued						471,202	416,666