Change in Accounting Principle (Tables)

12 Months Ended

Dec. 31, 2017

Change in Accounting Principle

Schedule of cumulative effect of the change in accounting principle

					Reported after
	As Previously			Cumulative	the Effect of a Change in
	Reported		Effect Adjustment		Accounting Principle
Balance Sheet Accounts Impacted by	December 31,		at the Beginning		at the Beginning
September 2012 and 2014 Warrants	2016		of 2017		of 2017
	(in thousands)
Warrant Liability - Related Party	$	976	$	(976)	$	—
Warrant Liability		922		(922)		—
Additional Paid-in Capital		495,455		19,046		514,501
Accumulated Deficit		(488,037)		(17,148)		(505,185)