Share-Based Payments - 2017 Share Incentive Plan (Details) $ / shares in Units, $ in Thousands		5 Months Ended	12 Months Ended
	Jul. 26, 2017 shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) item $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($) $ / shares shares
Additional disclosures
Share-based compensation expense | $			$ 9,748	$ 5,154	$ 5,732
2017 Share Incentive Plan
Options
Outstanding at beginning of year (in shares)			2,398,425	294,100
Granted (in shares)			2,463,300	2,199,225	294,100
Exercised (in shares)			0	0	0
Forfeited (in shares)			(439,061)	(94,900)
Outstanding at end of year (in shares)		4,422,664	4,422,664	2,398,425	294,100
Vested and exercisable at end of year (in shares)		1,120,280	1,120,280	119,287
Weighted average exercise price in $ per share
Outstanding balance at beginning of year (in dollars per share) | $ / shares			$ 5.41	$ 6.92
Granted (in dollars per share) | $ / shares			1.95	5.27	$ 6.92
Forfeited (in dollars per share) | $ / shares			4.79	6.75
Outstanding balance at end of year (in dollars per share) | $ / shares		$ 3.55	3.55	5.41	$ 6.92
Vested and exercisable balance at end of year (in dollars per share) | $ / shares		$ 5.53	$ 5.53	$ 6.88
Additional disclosures
Weighted average remaining contractual life			8 years 8 months 12 days
2017 Share Incentive Plan | $1.46 per share to $8.35 per share
Additional disclosures
Exercise price minimum range | $ / shares			$ 1.46
Exercise price maximum range | $ / shares			$ 8.35
2017 Share Incentive Plan | Ordinary Shares
Share-Based Payments
Number of shares authorized	3,000,000
Additional shares authorized	3,438,990
Shares available for grant		1,634,766	1,634,766
2017 Share Incentive Plan | Ordinary Shares | Minimum
Share-Based Payments
Annual increase, to be added on the first day of each fiscal year (in shares)	2,000,000
Annual increase, to be added on the first day of each fiscal year (as a percent)	4.00%
2017 Share Incentive Plan | Stock Options
Share-Based Payments
Exercise period			10 years
Fair Value Assumptions
Expected term of options (in years)			6 years	6 years 1 month 6 days	6 years
Dividend yield (as a percent)			0.00%	0.00%	0.00%
Additional disclosures
Share-based compensation expense | $			$ 2,600	$ 1,800	$ 100
Weighted-average grant date fair value (in dollars per share) | $ / shares			$ 1.14	$ 3.06	$ 3.98
Total unrecognized compensation related to unvested options | $		$ 4,900	$ 4,900
Recognition period			2 years 8 months 12 days
2017 Share Incentive Plan | Stock Options | Minimum
Fair Value Assumptions
Expected volatility (as a percent)			61.40%	59.80%	59.50%
Risk-free interest rate (as a percent)			1.90%	2.60%	1.90%
2017 Share Incentive Plan | Stock Options | Maximum
Fair Value Assumptions
Expected volatility (as a percent)			63.10%	61.40%	63.00%
Risk-free interest rate (as a percent)			2.60%	3.00%	2.30%
2017 Share Incentive Plan | SARs
Share-Based Payments
Exercise period			10 years
2017 Share Incentive Plan | Restricted Stock Units ("RSUs")
Additional disclosures
Share-based compensation expense | $			$ 200
Recognition period			9 months 18 days
Restricted Stock Units
Number of shares outstanding			1,222,100
Granted			479,000	1,241,450
Vested and issued			(657,581)
Forfeited			(141,833)	(19,350)
Number of shares outstanding		901,686	901,686	1,222,100
weighted average fair value per share
Weighted average fair value at the beginning | $ / shares			$ 3.31
Granted | $ / shares			1.90	$ 3.36
Vested and issued | $ / shares			3.18
Forfeited | $ / shares			2.79	6.47
Weighted average fair value at the end | $ / shares		$ 3.69	$ 3.69	$ 3.31
Additional Disclosures
Unrecognized compensation costs | $		$ 2,400	$ 2,400
Percentage that vests during the period			25.00%
Vesting period			4 years
Fair Value | $			$ 2,100
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | XENLETA
Additional disclosures
Share-based compensation expense | $		$ 1,400
Restricted Stock Units
Number of shares outstanding		161,175	161,175
Additional Disclosures
Number of shares vested			170,400
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | CONTEPO
Restricted Stock Units
Granted				35,600
Number of shares outstanding		35,600	35,600
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | Employees
Additional disclosures
Share-based compensation expense | $			$ 1,100	$ 200
Restricted Stock Units
Number of shares outstanding		225,911	225,911
Additional Disclosures
Number of shares vested			487,181
Number of vesting periods | item			3
Vesting period			6 months
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | Immediate vesting upon regulatory approval | XENLETA
Additional Disclosures
Percentage that vests during the period				50.00%
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | Immediate vesting upon regulatory approval | CONTEPO
Additional Disclosures
Percentage that vests during the period				50.00%
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | Vesting upon the one-year-anniversary of FDA approval | XENLETA
Additional Disclosures
Percentage that vests during the period				50.00%
2017 Share Incentive Plan | Restricted Stock Units ("RSUs") | Vesting upon the one-year-anniversary of FDA approval | CONTEPO
Additional Disclosures
Percentage that vests during the period				50.00%