Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

	Year Ended December 31,
	2018		2017
	(In thousands)
Current:
Federal	$	—	$	—
State		3		—
Foreign		106		—
Total Current	$	109	$	—
Deferred:
Federal	$	—	$	—
State		—		—
Foreign		—		—
Total Deferred	$	—	$	—
Provision for income taxes	$	109	$	—

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]

	December 31, 2018		December 31, 2017
Deferred tax assets:	(In thousands)
Net operating loss carry-forwards	$	43,822	$	19,441
Research and development tax credits		3,357		2,979
Capitalized research and development		2,326		—
Sale of future royalties		8,383		—
Accruals, reserves and other		714		544
Total deferred tax assets		58,602		22,964
Valuation allowance		(48,626)		(22,964)
Deferred tax assets net of valuation allowance		9,976		—
Deferred tax liabilities:
Intangible assets		(9,976)		—
Total deferred tax liabilities		(9,976)		—
Net deferred tax assets	$	—	$	—

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

	Year Ended December 31,
	2018		2017
U.S. federal taxes at statutory rate		21.0  %		34.0 %
State taxes (net of federal benefit)		0.6		14.2
Foreign rate differential		3.1		—
Global intangible low-taxed income		(8.8)		—
Permanent items:
Convertible note interest		(0.4)		(10.8)
Revaluation of derivative liabilities		—		11.9
Others		(2.1)		(1.4)
Tax credits		2.1		8.0
Change in valuation allowance		(20.4)		43.4
Impact of tax reform rate change		—		(97.0)
NOL and credit adjustments		(3.8)		(2.4)
Bargain purchase gain		8.1		—
Other		—		0.1
Provision for income taxes		(0.6)%		—%

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

	Year Ended December 31,
	2018		2017
	(in thousands)
Beginning Balance	$	1,404	$	1,231
Additions based on tax positions related to the current year		181		173
Decreases related to prior years’ tax positions		(3)		—
Ending Balance	$	1,582	$	1,404