Common stock and convertible preferred stock - Common Stock (Details)						9 Months Ended
	Aug. 04, 2021 shares	Apr. 28, 2021 USD ($) $ / shares item shares	Oct. 13, 2020 USD ($) $ / shares	Oct. 13, 2020 $ / shares shares	Oct. 06, 2020 $ / shares shares	Sep. 30, 2021 USD ($) Vote $ / shares shares	Dec. 31, 2020 $ / shares shares	Sep. 30, 2020 $ / shares
Common stock voting right | Vote						1
Stock issued | shares	14,115
Proceeds from issuance of common stock | $			$ 41,700,000			$ 1,338,000
Payments of underwriting discounts and commissions | $			$ 3,100,000
Common Stock, Par or Stated Value Per Share						$ 0.0001	$ 0.0001
Common Stock, Shares Authorized | shares						200,000,000	200,000,000
Fair value of common stock						$ 23.61		$ 1.95
IPO And Over-Allotment Option
Stock issued | shares					3,737,500
IPO
Stock issued | shares					3,250,000
Share price					$ 12.00
Common Stock, Par or Stated Value Per Share					$ 0.0001
Common Stock, Shares Authorized | shares					200,000,000
Preferred Stock, Shares Authorized | shares					10,000,000
Preferred Stock, Par or Stated Value Per Share					$ 0.0001
Over-Allotment Option
Stock issued | shares				487,500
Share price			$ 12.00	$ 12.00
Private offering
Share price		$ 27.00
Proceeds from issuance of common stock | $		$ 27,000,000.0
Units Issued During Period, New Issues | shares		1,000,000
Number of share for company's common stock | item		1
Number of warrants | shares		1
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 45.00
Warrants and Rights Outstanding, Term		3 years
Fair Value of Warrants | $		$ 6,000,000.0
Fair value of common stock		$ 28.70
Volatility rate
Warrants and Rights Outstanding, Measurement Input		82.7
Risk-free interest rate
Warrants and Rights Outstanding, Measurement Input		0.35
Expected term (in years)
Warrants and Rights Outstanding, Measurement Input | $		3
Strike price (per share)
Warrants and Rights Outstanding, Measurement Input		45.00