Business Description, Basis of Presentation and Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	12 Months Ended		48 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Jan. 01, 2018	Dec. 31, 2017
Business Description, Basis of Presentation and Significant Accounting Policies
Current inventory	$ 11,441	$ 13,228	$ 11,441
Long-term inventory	6,284	8,953	6,284
Operating lease right-of-use assets	2,459		2,459
Operating lease liability	2,021		2,021
Deferred rent		135
Deferred product revenue	173	283	173
Decreased revenue due to the impact of the adoption of the New Revenue Standard	25,042	28,156
Advertising expenses	902	1,037
Net deferred tax assets	0		0
Cash and cash equivalents	4,064	11,211	4,064		$ 5,571
Working capital	18,934	28,357	18,934
Net cash used in operating activities	4,656	6,621
Decrease of cash used in operating activities	1,965
Litigation for Intellectual Property Infringement
Business Description, Basis of Presentation and Significant Accounting Policies
Litigation Settlement, Expense			13,591
Equipment Sales
Business Description, Basis of Presentation and Significant Accounting Policies
Decreased revenue due to the impact of the adoption of the New Revenue Standard	24,513
Software and Licenses
Business Description, Basis of Presentation and Significant Accounting Policies
Decreased revenue due to the impact of the adoption of the New Revenue Standard	529
Retained Earnings
Business Description, Basis of Presentation and Significant Accounting Policies
Change in Accounting Policy, recognized an adjustment to increase retained earnings		2,782
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
Business Description, Basis of Presentation and Significant Accounting Policies
Deferred product revenue				$ (4,337)
Distributor channel inventories				(1,555)
Decreased revenue due to the impact of the adoption of the New Revenue Standard		1,252
Accounting Standards Update 2014-09 | Retained Earnings | Difference between Revenue Guidance in Effect before and after Topic 606
Business Description, Basis of Presentation and Significant Accounting Policies
Change in Accounting Policy, recognized an adjustment to increase retained earnings				$ 2,782
Accounting Standards Update 2016-02
Business Description, Basis of Presentation and Significant Accounting Policies
Operating lease right-of-use assets		2,966
Operating lease liability		3,101
Deferred rent		135
Minimum
Business Description, Basis of Presentation and Significant Accounting Policies
Intangible assets, estimated useful lives	3 years
Maximum
Business Description, Basis of Presentation and Significant Accounting Policies
Intangible assets, estimated useful lives	10 years
Replacement Parts
Business Description, Basis of Presentation and Significant Accounting Policies
Current inventory	$ 102	$ 184	$ 102