11. Net loss per share

Basic and diluted net loss per share attributable to common stockholders was calculated as follows:


	Year Ended December 31,
	2019		2018
Numerator:
Net loss	$	(43,755)	$	(81,714)
Accretion of redeemable convertible preferred stock to redemption value		—		(520)
Net loss attributable to common stockholders, basic and diluted	$	(43,755)	$	(82,234)
Denominator:
Weighted average common shares outstanding, basic and diluted		15,070,728		103,403
Net loss per share attributable to common stockholders, basic and diluted	$	(2.90)	$	(795.28)

The Company excluded 49,568 shares and 125,790 shares of restricted common stock, presented on a weighted average basis, from the calculations of basic net loss per share attributable to common stockholders for the years ended December 31, 2019 and 2018, respectively, because those shares had not vested.

The Company’s potentially dilutive securities, which include stock options, unvested restricted common stock and redeemable convertible preferred stock, have been excluded from the computation of diluted net loss per share attributable to common stockholders as the effect would be to reduce the net loss per share. Therefore, the weighted average number of common shares outstanding used to calculate both basic and diluted net loss per share attributable to common stockholders is the same. The Company excluded the following potential common shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to common stockholders for the periods indicated because including them would have had an anti-dilutive effect:


	Year Ended December 31,
	2019	2018

Options to purchase common stock	3,096,555	1,839,913
Unvested restricted common stock	155,149	80,190
Redeemable convertible preferred stock (as converted to common stock)	—	21,056,136
	3,251,704	22,976,239