Note 2 - Basis of Presentation and Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

	Balance at			Adjustments			Balance at
	December 31,			Due to			January 1,
	2018			Topic 842			2019
Balance Sheet:
Assets
Property, plant and equipment, net	$	8,130,708		$	(107,734	)	$	8,022,974
Operating lease right-of-use assets, net		—			3,985,071			3,985,071
Liabilities
Deferred rent		2,674,683			(2,674,683	)		—
Operating lease liabilities		—			6,659,725			6,659,725
Finance lease liabilities		828,785			1,636,185			2,464,970
Long-term debt		11,944,549			(1,141,792	)		10,802,757
Stockholders’ equity (deficit)
Accumulated deficit		(167,053,897	)		(602,098	)		(167,655,995	)

Schedule of Property, Plant and Equipment, Useful Life [Table Text Block]

Lab and build-to-suit equipment (years)	5	-	7
Office equipment (years)		5
Furniture and fixtures (years)		10
Computer equipment (years)		3
Leasehold improvements	Lesser of life of the asset or remaining lease term

Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block]

	Year Ended December 31,
	2019		2018
Stock Options		1,979,411		1,658,112
Warrants		111,372		170,925
Total		2,090,783		1,829,037

Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis [Table Text Block]

			Significant
	Quoted Prices		Other
	in Active		Observable		Significant
	Markets		Inputs		Unobservable		Carrying
December 31, 2019	(Level 1)		(Level 2)		Inputs (Level 3)		Value
Pacific Western Bank note - A&R LSA	$	—	$	14,094,792	$	—	$	15,878,121

			Significant
	Quoted Prices		Other
	in Active		Observable		Significant
	Markets		Inputs		Unobservable		Carrying
December 31, 2018	(Level 1)		(Level 2)		Inputs (Level 3)		Value
Pacific Western Bank Tranche I note - A&R LSA	$	—	$	10,412,650	$	—	$	10,802,355
CSC build-to-suit equipment financing		—		1,311,135		—		1,142,194
Total	$	—	$	11,723,785	$	—	$	11,944,549