Operating Leases - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) ft² term	Jun. 30, 2018 USD ($)
Lessee, Lease, Description [Line Items]
Operating lease cost (including related operating costs)	$ 71,000		$ 146,000
Short-term lease cost	$ 53,000		$ 129,000
Canada
Lessee, Lease, Description [Line Items]
Office space, square foot | ft²			31,100
Lease term	5 years		5 years
Renewal option | term			1
Renewal term	5 years		5 years
Monthly rent			$ 13,000
Related operating expenses			12,300
Operating lease cost (including related operating costs)	$ 71,000		146,000
Rent expense Under ASC 840				$ 161,000
Massachusetts
Lessee, Lease, Description [Line Items]
Monthly rent			8,000
Rent expense Under ASC 840		$ 36,000		62,000
Short-term lease cost	24,000		51,000
Pennsylvania
Lessee, Lease, Description [Line Items]
Monthly rent			11,000
Rent expense Under ASC 840		$ 32,000		$ 56,000
Short-term lease cost	$ 29,000		$ 78,000