Note 2 - Summary of Significant Accounting Policies - Impact of New Standard on Consolidated Balance Sheet and Consolidated Statements of Operations (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2019
Revenue		$ 6,567,000	$ 18,517,000
Cost of revenue		5,551,000	11,197,000
Gross profit		1,016,000	7,320,000
Loss from operations		(30,679,000)	(44,965,000)
Comprehensive and net loss		$ (42,526,000)	$ (49,981,000)
Basic and diluted (in dollars per share)		$ (34.39)	$ (160.92)
Weighted average shares (in shares)		1,247,768	310,589
Accrued liabilities		$ 4,698,000	$ 6,766,000	$ 6,996,000
Other noncurrent liabilities		167,000	634,000	$ 1,033,000
Accumulated deficit		$ (197,911,000)	(155,385,000)
Accounting Standards Update 2014-09 [Member]
Gross profit			749,000
Accumulated deficit			177,000
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
Revenue			17,780,000
Cost of revenue			11,209,000
Gross profit			6,571,000
Loss from operations			(45,714,000)
Comprehensive and net loss			$ (50,730,000)
Basic and diluted (in dollars per share)			$ (163.33)
Weighted average shares (in shares)			310,589
Accrued liabilities			$ 7,014,000
Other noncurrent liabilities			1,313,000
Accumulated deficit			(156,311,000)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
Revenue	[1]		737,000
Cost of revenue	[2]		(12,000)
Gross profit	[3]		749,000
Loss from operations	[3]		749,000
Comprehensive and net loss	[3]		$ 749,000
Basic and diluted (in dollars per share)			$ 2.41
Weighted average shares (in shares)
Accrued liabilities	[4]		$ (248,000)
Other noncurrent liabilities	[5]		(679,000)
Accumulated deficit	[6]		$ 926,000

[1] Change relates to revenue from extended assurance warranties for which no deferral is required on the adoption of ASC 606.

[2] Change relates to the future costs associated with extended assurance warranties required to be recorded on the adoption of ASC 606.

[3] Change relates to the net gain adjustment on the adoption of ASC 606.

[4] Change relates to the current portion of deferred revenue in connection with the extended warranties not required to be recorded under ASC 606, partially offset by future costs associated with extended warranties required to be recorded on the adoption of ASC 606.

[5] Change relates to noncurrent portion of deferred revenue in connection with the extended warranties not required to be recorded under ASC 606.

[6] Change relates to $177,000 cumulative effect adjustment on the adoption of ASC 606 and the net gain adjustment of $749,000 for the year ended December 31, 2018.