Commitments and Contingencies - Operating Leases (Details) $ in Thousands	1 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	May 31, 2017 USD ($)	Dec. 31, 2016 USD ($) ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Other Commitments [Line Items]
Rent expense recorded					$ 565	$ 494
Notice of termination period				30 days
Canada
Other Commitments [Line Items]
Minimum monthly rent				$ 2
Corporate Headquarter, Cambridge Massachusetts
Other Commitments [Line Items]
Lease term	4 months
Minimum monthly rent	$ 11
Rent expense recorded				119
Willow Grove, PA Office Space
Other Commitments [Line Items]
Lease term		1 year
Minimum monthly rent		$ 2
Rent expense recorded				18
Philadelphia, PA Office Space
Other Commitments [Line Items]
Lease term	6 months
Minimum monthly rent	$ 7
Rent expense recorded	$ 5
Majority Shareholder | Facility in Winnipeg, Manitola
Other Commitments [Line Items]
Lease square footage | ft²			31,400
Lease term			5 years
Minimum monthly rent				28
Related party transaction, amounts of transaction			$ 86	$ 320