Stockholders' equity (Details)			12 Months Ended
	Sep. 02, 2022 USD ($)	May 16, 2022 $ / shares shares	Dec. 31, 2022 USD ($) Vote $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 shares	Nov. 12, 2020 USD ($)
Common stock
Stock, shares authorized			440,000,000
Common stock, shares authorized			400,000,000	400,000,000
Common stock, par value (in dollars per share) | $ / shares			$ 0.001	$ 0.001
Preferred stock, shares authorized			40,000,000
Preferred stock, par value (in dollars per share) | $ / shares			$ 0.001
Proceeds from at-the-market sales of common stock, net | $			$ 682,973	$ 1,538,645
Number of voting rights per common share | Vote			1
Shelf Registration Statement
Maximum amount to be issued under universal shelf registration statement | $						$ 350,000,000.0
Common Stock
Common stock
Conversion of preferred stock into common stock (in shares)			1,446,701
Series A Convertible Preferred Stock
Common stock
Conversion of preferred stock into common stock (in shares)			2,893,403
Number of shares remained to be converted into common stock			56,227
Atrin Pharmaceuticals, Inc | Common Stock
Common stock
Common stock, par value (in dollars per share) | $ / shares		$ 0.001
Issuance of stock upon acquisition of Atrin (in shares)		55,869
Atrin Pharmaceuticals, Inc | Series A Convertible Preferred Stock
Common stock
Issuance of stock upon acquisition of Atrin (in shares)		2,949,630
Preferred stock conversion ratio		10
ATM offering
Common stock
Number of shares issued			38,481	18,338	0
Commission payable as a percentage of gross proceeds from sale of common stock under ATM offering	3.00%
Proceeds from at-the-market sales of common stock, net | $			$ 700,000	$ 1,500,000
Shelf Registration Statement
Maximum amount to be issued under at-the-market offering program | $	$ 14,744,728