Fair Value Measurements - Summary of Changes in Fair Value for the Level 3 Liabilities (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	$ (4,559)
Purchases, sales, issuances and settlements (net)	(72)
Unrealized gains/(losses)	2,807
Ending balance	(1,824)
Equity Warrant Liability
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance	(4,559)
Unrealized gains/(losses)	2,884
Ending balance	(1,675)
Stock Appreciation Rights
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Purchases, sales, issuances and settlements (net)	(72)
Unrealized gains/(losses)	(77)
Ending balance	$ (149)