For an unclassified balance sheet, the amount due from customers or clients for goods or services that have been delivered or sold in the normal course of business, reduced to their estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(9))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(5))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Note 2 - Revenue Recognition (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Retained Earnings (Accumulated Deficit), Ending Balance	$ (27,337)		$ (27,337)			$ (27,089)
Capitalized Contract Cost, Net, Total					$ 500
Revenue from Contract with Customer, Including Assessed Tax	20,213	$ 26,517	66,069	$ 75,094
Contract with Customer, Liability, Noncurrent	300		300		900
Contract with Customer, Liability, Revenue Recognized	4,400		12,000
Revenue, Remaining Performance Obligation, Amount	38,700		38,700
Contract with Customer, Performance Obligation Satisfied in Previous Period	1,300		1,600
Capitalized Contract Cost, Amortization	100		300
Capitalized Contract Cost, Impairment Loss	0		0
Prepaid Expenses and Other Current Assets [Member]
Contract with Customer, Asset, Net, Current, Total	3,100		3,100		1,900
Prepaid Expenses and Other Current Assets and Other Non-current Assets [Member]
Deferred Costs, Total	$ 400		$ 400			$ 600
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Transferred over Time [Member]
Concentration Risk, Percentage	59.00%		66.00%
Customer Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Transferred at Point in Time [Member]
Concentration Risk, Percentage	41.00%		34.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member]
Revenue from Contract with Customer, Including Assessed Tax	$ 20,213	$ 26,517	$ 66,069	$ 75,094
Concentration Risk, Percentage	100.00%	100.00%	100.00%	100.00%
Geographic Concentration Risk [Member] \| Sales Revenue, Net [Member] \| Countries other than the United States [Member]
Concentration Risk, Percentage	59.00%	63.00%	58.00%	58.00%
Accounting Standards Update 2014-09 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance					(4,400)
Accounts Receivable, Net, Total					800
Contract with Customer, Asset, Net, Total					1,900
Contract with Customer, Liability, Total					$ (2,500)
Accounting Standards Update 2014-09 [Member] \| Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance	$ (4,679)		$ (4,679)
Revenue from Contract with Customer, Including Assessed Tax	$ (522)		$ (539)