Summary of Significant Accounting Policies (Details) $ in Thousands		1 Months Ended			3 Months Ended
	May 09, 2017 shares	May 31, 2017 USD ($) shares	Feb. 29, 2016 shares	Sep. 30, 2013 shares	Mar. 31, 2017 USD ($) director	Jul. 31, 2016 shares	Dec. 31, 2016 USD ($)
Restricted Cash
Restricted Cash Current | $							$ 67
Restricted Cash Non Current | $					$ 60		60
Deferred Offering Costs
Deferred offering costs | $					$ 2,399		134
Warrant Liability
Number of directors to whom the Company agreed to issue warrants | director					2
Contingent Equity Liability
Issuance of common shares			429,000			1,090,500
Certificate of deposit
Restricted Cash
Restricted Cash Non Current | $					$ 60		60
Series A preferred shares
Restricted Cash
Restricted Cash Current | $					$ 0		$ 67
Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares	9,900,000
Fair value of contingent equity liabilities | $		$ 32,020
Product related collaborative arrangements | BMS Agreement
Contingent Equity Liability
Issuance of common shares		1,345,374
Product related collaborative arrangements | BMS Agreement | Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares		1,345,374
Product related collaborative arrangements | AstraZeneca
Contingent Equity Liability
Issuance of common shares		538,149
Product related collaborative arrangements | AstraZeneca | Initial public offering | Subsequent Event
Contingent Equity Liability
Issuance of common shares		538,149
Collaborative arrangement | Yale Agreement
Contingent Equity Liability
Issuance of common shares				250,000