Fair Value Measurements - Schedule of Financial Instruments Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	$ 31,589	$ 31,589		$ 7,449
Unrealized gains (losses)		5	$ 0
Other Expense [Member]
Summary of financial instruments measured at fair value on a recurring basis
Unrealized gains (losses)	(20)	5
Other Comprehensive Income (Loss) [Member]
Summary of financial instruments measured at fair value on a recurring basis
Unrealized gains (losses)			$ 100
Common Shares of Co Two Solution [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	676	676		671
Money Market Funds [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	30,913	30,913		6,778
Level 1 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	30,913	30,913		6,778
Level 1 [Member] | Common Shares of Co Two Solution [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	0	0		0
Level 1 [Member] | Money Market Funds [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	30,913	30,913		6,778
Level 2 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	676	676		671
Level 2 [Member] | Common Shares of Co Two Solution [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	$ 676	$ 676		671
Investment owned (shares)	10,000,000	10,000,000
Level 2 [Member] | Money Market Funds [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	$ 0	$ 0		0
Level 3 [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	0	0		0
Level 3 [Member] | Common Shares of Co Two Solution [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	0	0		0
Level 3 [Member] | Money Market Funds [Member]
Summary of financial instruments measured at fair value on a recurring basis
Financial assets	$ 0	$ 0		$ 0