Share-based compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based compensation

Schedule of share-based compensation expense by classification included in consolidated statements of operations and comprehensive loss

	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
	(in thousands)				(in thousands)
Research and development	$	2,889	$	2,119	$	5,271	$	4,099
Selling, general and administrative		2,825		2,457		4,783		4,755
Total	$	5,714	$	4,576	$	10,054	$	8,854

Schedule of share-based compensation expense

	Three months ended June 30,				Six months ended June 30,
	2020		2019		2020		2019
	(in thousands)				(in thousands)
Award type
Share options	$	2,746	$	2,004	$	4,954	$	4,080
Restricted share units (“RSUs”)		2,209		995		3,653		1,925
Performance share units (“PSUs”)		759		1,577		1,447		2,849
Total	$	5,714	$	4,576	$	10,054	$	8,854

Schedule of unrecognized compensation cost related to unvested awards

	Unrecognized		Weighted average
	share-based		remaining
	compensation		period for
	expense		recognition
	(in thousands)		(in years)
Award type
Share options	$	27,450	3.00
Restricted share units		15,705	2.28
Performance share units		3,519	1.37
Total	$	46,674	2.63

Schedule of weighted-average assumptions for fair value of option issued

	Three months ended June 30,		Six months ended June 30,
Assumptions	2020	2019	2020	2019
Expected volatility	70%	75%	70%	75%
Expected terms	10 years	10 years	10 years	10 years
Risk free interest rate	0.76% - 0.83%	2.17% - 2.63%	0.76% - 1.44%	2.17% - 2.87%
Expected dividend yield	0%	0%	0%	0%

Summary of RSUs activity

	RSU
		Weighted average
	Number of	grant-date fair
	ordinary shares	value
Non-vested at December 31, 2019	370,830	$	28.62
Granted	244,449	$	52.81
Vested	(171,401)	$	19.36
Forfeited	(14,562)	$	45.12
Non-vested at June 30, 2020	429,316	$	45.53
Total weighted average grant date fair value of RSUs granted during the period (in $ millions)		$	12.9

Summary of PSUs activity

	PSU
		Weighted average
	Number of	grant-date fair
	ordinary shares	value
Non-vested at December 31, 2019	479,422	$	21.17
Granted	91,003	$	57.56
Vested	(354,105)	$	17.44
Non-vested at June 30, 2020	216,320	$	42.58
Total weighted average grant date fair value of PSUs granted during the period (in $ millions)		$	5.2

2014 Plan

Share-based compensation

Summary of option activity

	Options
	Number of	Weighted average
	ordinary shares	exercise price
Outstanding at December 31, 2019	2,683,104	$	21.29
Granted	470,327	$	53.26
Forfeited	(69,758)	$	36.13
Exercised	(203,940)	$	16.68
Outstanding at June 30, 2020	2,879,733	$	26.47
Thereof, fully vested and exercisable at June 30, 2020	1,530,724	$	16.06
Thereof, outstanding and expected to vest after June 30, 2020	1,349,009	$	38.30

Total weighted average grant date fair value of options issued during the period (in $ millions)	$	14.2
Proceeds from option sales during the period (in $ millions)	$	3.4