Consolidated Statements of Changes in Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock/Ordinary Shares	Treasury Shares	Additional paid in capital	Accumulated other comprehensive income (loss)	Accumulated deficit	Total
Stockholders' equity, beginning balance at Dec. 31, 2015	$ 2,308	$ (22)	$ 256,412	$ (40)	$ (149,952)	$ 108,706
Stockholders' equity, beginning balance (in shares) at Dec. 31, 2015	2,120	3
Consolidated Statements of Changes in Stockholders' Equity
Issuance of common stock	$ 618		24,204			24,822
Issuance of common stock (in shares)	588
Exercise of stock options	$ 13	$ 22	235			270
Exercise of stock options (in shares)	12	(3)
Equity transaction costs			(4,247)			(4,247)
Stock-based compensation expense			2,545			2,545
Other comprehensive income, net of tax				50		50
Net loss					(54,890)	(54,890)
Stockholders' equity, ending balance at Dec. 31, 2016	$ 2,939		279,149	10	(204,842)	77,256
Stockholders' equity, ending balance (in shares) at Dec. 31, 2016	2,720
Consolidated Statements of Changes in Stockholders' Equity
Issuance of common stock	$ 94		79,906			80,000
Issuance of common stock (in shares)	9,412
Exercise of stock options	$ 3		51			54
Exercise of stock options (in shares)	54
Equity transaction costs			(6,635)			(6,635)
Redomiciliation share exchange	$ (2,669)		2,669
Redomiciliation share exchange (in shares)	24,522
Stock-based compensation expense			5,732			5,732
Other comprehensive income, net of tax				17		17
Net loss					(74,356)	(74,356)
Stockholders' equity, ending balance at Dec. 31, 2017	$ 367		360,872	27	(279,198)	82,068
Stockholders' equity, ending balance (in shares) at Dec. 31, 2017	36,708
Consolidated Statements of Changes in Stockholders' Equity
Issuance of common stock	$ 230		73,989			74,219
Issuance of common stock (in shares)	22,974
Equity transaction costs			(4,933)			(4,933)
Stock-based compensation expense			5,154			5,154
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc.	$ 73		26,829			26,902
Shares issued in connection with the acquisition of Zavante Therapeutics, Inc. (in shares)	7,337
Net loss					(114,780)	(114,780)
Stockholders' equity, ending balance at Dec. 31, 2018	$ 670		$ 461,911	$ 27	$ (393,978)	$ 68,630
Stockholders' equity, ending balance (in shares) at Dec. 31, 2018	67,019