Net loss per common stock (Tables)

9 Months Ended

Sep. 30, 2019

Earnings Per Share [Abstract]

Schedule of basic and diluted net loss per common stock

	THREE MONTHS ENDED SEPTEMBER 30,				NINE MONTHS ENDED SEPTEMBER 30,
	2019		2018		2019		2018
Outstanding stock options		6,203,993		3,357,264		6,203,993		3,357,264
Restricted stock units		72,000		—		72,000		—
Common stock to be issued on conversion of convertible preferred stock		10,192,700		—		10,192,700		—
		16,468,693		3,357,264		16,468,693		3,357,264