Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 4,169	$ 4,948
Less accumulated depreciation	(2,336)	(2,057)
Property and Equipment, Net	1,833	2,891
Office furniture and equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	1,752	2,073
Office furniture and equipment | Minimum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Life	3 years
Office furniture and equipment | Maximum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Life	7 years
Rental inventory
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	1,342	2,142
Property and Equipment, Useful Life	5 years
Vehicles
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	76	76
Property and Equipment, Useful Life	5 years
Leasehold improvements
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	874	486
Leasehold improvements | Minimum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Life	2 years
Leasehold improvements | Maximum
Property Plant And Equipment [Line Items]
Property and Equipment, Useful Life	6 years
Assembly equipment
Property Plant And Equipment [Line Items]
Property and Equipment, Gross	$ 125	$ 171
Property and Equipment, Useful Life	7 years