Note Payable - Schedule of Aggregate Annual Future Payments Due on IPA Agreements (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Line of Credit Facility [Line Items]
Less current portion	$ (37)	$ (255)
IPA Agreements | Notes Payable
Line of Credit Facility [Line Items]
2019 (remaining three months)	37
Total payments	37
Less amount representing interest	0
Total note payable	37	$ 300
Less current portion	(37)
Note payable, net of current portion	$ 0