Revenue, Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenue [Abstract]
Lease term	36 months
Notice period to cancel contract agreement	60 days
Contract with Customer, Liability [Abstract]
Short-term contract liabilities	$ 169
Long-term contract liabilities	254
Change in Contract with Customer, Liability [Abstract]
Contract liabilities recognized as revenue	39
Co-pay reimbursements recorded as reduction of revenue	$ (155)	$ (126)