13. Net loss per share

Basic and diluted net loss per share attributable to ordinary shareholders was calculated as follows (in thousands, except share and per share amounts):


	Year Ended
	December 31,
	2019		2018		2017
Numerator:
Net loss attributable to ordinary shareholders	$	(30,608)	$	(21,846)	$	(16,259)
Denominator:
Weighted average ordinary shares outstanding, basic and diluted		11,045,370		438,862		333,125
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(2.77)	$	(49.78)	$	(48.81)

The Company’s potentially dilutive securities, which include share options, warrants to subscribe for ordinary shares, and which prior to the completion of the IPO, included convertible preferred shares, warrants to subscribe for Series A and Series B1 Preferred Shares, and unvested restricted shares, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of ordinary shares outstanding used to calculate both basic and diluted net loss per share attributable to ordinary shareholders is the same. The Company excluded the following potentially dilutive ordinary shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to ordinary shareholders for the periods indicated because including them would have had an anti‑dilutive effect:


	Year Ended
	December 31,
	2019	2018	2017
Convertible preferred shares (as converted to ordinary shares)	—	11,532,659	9,641,740
Warrants to subscribe for convertible preferred shares (as adjusted to reflect the impact of the share capital reorganization and issuance of bonus shares (Note 1))(1)(2)	92,885	1,347,953	1,347,953
Restricted ordinary shares	—	83,947	162,466
Options to purchase ordinary shares	2,634,346	863,712	964,538
	2,727,231	13,828,271	12,116,697

⁽¹⁾

On March 7, 2019, the holders of the Series B1 warrants to subscribe for Series B1 Preferred Shares agreed that 50% of the warrants would be exercised in conjunction with the IPO and 50% of the warrants would expire.

⁽²⁾

At December 31, 2019 65,000 warrants are outstanding which are exercisable into 92,885 ordinary shares (Note 6).