Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock/Ordinary Shares	Additional paid in capital	Accumulated other comprehensive income	Accumulated deficit	Total
Stockholders' equity, beginning balance at Dec. 31, 2017	$ 37	$ 361,202	$ 27	$ (279,198)	$ 82,068
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2017	3,671
Consolidated Statements of Changes in Stockholders' Equity
Issuance of ordinary shares	$ 23	74,196			74,219
Issuance of ordinary shares (in shares)	2,297
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc.	$ 7	26,895			26,902
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc. (in shares)	734
Equity transaction costs		(4,933)			(4,933)
Stock-based compensation expense		5,154			5,154
Net loss				(114,780)	(114,780)
Stockholders' equity, ending balance at Dec. 31, 2018	$ 67	462,514	27	(393,978)	68,630
Stockholders' equity, ending balance (in shares) at Dec. 31, 2018	6,702
Consolidated Statements of Changes in Stockholders' Equity
Issuance of ordinary shares and warrants	$ 26	48,056			48,082
Issuance of ordinary shares and warrants (in shares)	2,584
Shares issued in connection with the vesting of restricted stock units	$ 1	(1)
Shares issued in connection with the vesting of restricted stock units (in shares)	66
Shares issued in connection with the employee stock purchase plan		372			372
Shares issued in connection with the employee stock purchase plan (in shares)	21
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc.	$ 1	(1)
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc. (in shares)	82
Equity transaction costs		(2,794)			(2,794)
Stock-based compensation expense		9,748			9,748
Net loss				(82,764)	(82,764)
Stockholders' equity, ending balance at Dec. 31, 2019	$ 95	517,894	27	(476,742)	41,274
Stockholders' equity, ending balance (in shares) at Dec. 31, 2019	9,455
Consolidated Statements of Changes in Stockholders' Equity
Issuance of ordinary shares	$ 116	60,944			61,060
Issuance of ordinary shares (in shares)	11,571
Shares issued in connection with the vesting of restricted stock units (in shares)	44
Shares issued in connection with the employee stock purchase plan		43			43
Shares issued in connection with the employee stock purchase plan (in shares)	9
Equity transaction costs		(4,977)			(4,977)
Stock-based compensation expense		5,219			5,219
Net loss				(69,484)	(69,484)
Stockholders' equity, ending balance at Dec. 31, 2020	$ 211	$ 579,123	$ 27	$ (546,226)	$ 33,135
Stockholders' equity, ending balance (in shares) at Dec. 31, 2020	21,079