Share-Based Payments - 2020 Share Incentive Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Mar. 04, 2020
Share-Based Payments
Share-based compensation expense	$ 5,219,000	$ 9,748,000	$ 5,154,000
Additional disclosures
Weighted-average remaining contractual life	8 years 8 months 12 days
Research and development
Share-Based Payments
Share-based compensation expense	$ 1,280,000	2,138,000	1,406,000
Selling, general and administrative
Share-Based Payments
Share-based compensation expense	$ 3,939,000	$ 7,610,000	$ 3,748,000
2020 Share Incentive Plan
Share-Based Payments
Options granted during the period	317,805
Exercise price (in dollars per share)	$ 10.24
Share-based compensation expense	$ 144,000,000
Grant date fair value	$ 4.40
Options
Granted (in shares)	317,805
Forfeited (in shares)	(21,000)
Outstanding at end of year (in shares)	296,805
Weighted average exercise price in $ per share
Granted (in dollars per share)	$ 10.24
Forfeited (in dollars per share)	7.88
Outstanding balance at end of year (in dollars per share)	$ 10.18
Ordinary Shares | 2020 Share Incentive Plan
Share-Based Payments
Shares reserved for future issuance	820,022
Ordinary Shares | Maximum | 2020 Share Incentive Plan
Share-Based Payments
Shares reserved for future issuance				930,000
Stock Options | 2020 Share Incentive Plan
Share-Based Payments
Options granted during the period	296,805
Options
Granted (in shares)	296,805
Additional disclosures
Weighted-average remaining contractual life	9 years 7 months 6 days
Total unrecognized compensation related to unvested options	$ 1,300,000
Recognition period	1 year 7 months 6 days
Stock Options | Minimum | 2020 Share Incentive Plan
Share-Based Payments
Exercise price (in dollars per share)	$ 2.42
Weighted average exercise price in $ per share
Granted (in dollars per share)	$ 2.42
Fair Value Assumptions
Expected volatility (as a percent)	73.00%
Expected term of options (in years)	5 years 6 months
Risk-free interest rate (as a percent)	0.34%
Stock Options | Maximum | 2020 Share Incentive Plan
Share-Based Payments
Exercise price (in dollars per share)	$ 13.50
Weighted average exercise price in $ per share
Granted (in dollars per share)	$ 13.50
Fair Value Assumptions
Expected volatility (as a percent)	74.40%
Expected term of options (in years)	6 years 1 month 6 days
Risk-free interest rate (as a percent)	0.51%
Restricted Stock Units ("RSUs") | 2020 Share Incentive Plan | Employees
Share-Based Payments
Options granted during the period	45,977
Number of vesting periods	3
Vesting period	6 months
Grant date fair value	$ 7.88
Options
Granted (in shares)	45,977
Performance Based Restricted Stock Unit | 2020 Share Incentive Plan | Employees
Share-Based Payments
Options granted during the period	43,125
Share-based compensation expense	$ 111,000,000,000
Grant date fair value	$ 5.30
Options
Granted (in shares)	43,125
Additional disclosures
Total unrecognized compensation related to unvested RSUs	$ 500,000
Recognition period	1 year