Summary of significant accounting policies (Tables)

12 Months Ended

Dec. 31, 2019

Summary of significant accounting policies

Summary of useful lives of property and equipment

Asset category	Estimated useful life
Computer equipment and software	5 years
Furniture and fixtures	5 years
Laboratory equipment and office furniture	5 years
Leasehold improvements	Remainder of lease term

Schedule of basic and diluted net loss per share attributable to common stockholders

The following table sets forth the potentially dilutive securities that have been excluded from the calculation of diluted net loss per share because to include them would be anti‑dilutive (in common stock equivalent shares):

	Year ended December 31,
	2019	2018	2017
Series A convertible preferred stock	—	612,446	612,446
Series B convertible preferred stock	—	7,235,969	7,235,969
Series C convertible preferred stock	—	4,712,698	—
Options to purchase common stock	3,499,934	1,844,188	1,897,206
Total shares of common stock equivalents	3,499,934	14,405,301	9,745,621