Balance Sheet Components (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure Text Block Supplement [Abstract]

Cash, Cash Equivalents and Investments [Table Text Block]

	March 31, 2018
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
						(in thousands)
Money market funds	$	5,600	$	—	$	—	$	5,600	$	5,600
Corporate bonds		—		—		—		—		—
Total	$	5,600	$	—	$	—	$	5,600	$	5,600
Reported as:
Cash equivalents	$	5,600	$	—	$	—	$	5,600	$	5,600
Short-term investments		—		—		—		—		—
Total	$	5,600	$	—	$	—	$	5,600	$	5,600

	December 31, 2017
			Gross Unrecognized Gains		Gross Unrecognized Losses		Estimated Fair Value
	Amortized Cost								Carrying Value
						(in thousands)
Money market funds	$	1,192	$	—	$	—	$	1,192	$	1,192
Corporate bonds		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607
Reported as:
Cash equivalents	$	1,192	$	—	$	—	$	1,192	$	1,192
Short-term investments		1,415		—		—		1,415		1,415
Total	$	2,607	$	—	$	—	$	2,607	$	2,607

Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]

	March 31,  2018		December 31,  2017
	(in thousands)
Royalties receivable	$	11,939	$	—
Government contract - billed		230		477
Government contract - unbilled		112		153
Tax credit receivable		1,068		—
Accounts receivable, net of allowance	$	13,349	$	630

Property, Plant and Equipment [Table Text Block]

	March 31, 2018		December 31, 2017
	(in thousands)
Laboratory equipment	$	1,771	$	1,565
Office and computer equipment		296		175
Leasehold improvements		281		226
Total property and equipment		2,348		1,966
Less: accumulated depreciation		(1,334)		(1,236)
Property and equipment, net	$	1,014	$	730

Finite-lived Intangible Assets Amortization Expense [Table Text Block]

	March 31, 2018		December 31, 2017
	(in thousands)
Purchased technology	$	22,400	$	—
In-process research and development		1,600		—
Intellectual property		80		80
Total cost		24,080		80
Less accumulated amortization		453		40
Intangible assets, net	$	23,627	$	40

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]

	December 31, 2017
2018 (nine months remaining)	$	2,428
2019		2,254
2020		1,757
2021		1,758
2022		1,757
Thereafter		12,073
Total	$	22,027

Schedule of Accrued Liabilities [Table Text Block]

	March 31, 2018		December 31, 2017
	(in thousands)
Accrued compensation	$	1,076	$	1,320
Accrued clinical and manufacturing expenses		359		69
Accrued professional and consulting services		254		113
Convertible preferred stock warrant liability		—		67
Other		450		36
Total	$	2,139	$	1,605