Consolidated Balance Sheets and Statements of Operations and Comprehensive Loss Components - Inventories/Prepaid/PP&E (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Inventories, net:
Work-in-process	$ 1,478	$ 651
Finished goods	119	230
Inventories, net	1,597	881
Prepaid expenses and other:
Interest receivable	48	160
Prepaid insurance	134	143
Prepaid expenses and other	519	584
Total	701	887
Property and equipment, net:
Property and equipment, gross	5,980	5,005
Less: Accumulated depreciation and amortization	(4,350)	(4,151)
Property and equipment, net	1,630	854
Equipment, furniture and fixtures and leasehold improvements
Property and equipment, net:
Property and equipment, gross	5,646	4,255
Acquired software
Property and equipment, net:
Property and equipment, gross	$ 334	$ 750

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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