Restructuring Costs - Changes in Restructuring Balance (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
December 31, 2015	$ 0
Additional accruals	335,000	$ 0
Cash payments	(282,000)
Non-cash settlements	(34,000)
Accrued restructuring balance as of December 31, 2016	19,000	0
Employee Severance and Benefits
Restructuring Reserve [Roll Forward]
December 31, 2015	0
Additional accruals	301,000	0
Cash payments	(282,000)
Non-cash settlements	0
Accrued restructuring balance as of December 31, 2016	19,000	0
Asset Impairments
Restructuring Reserve [Roll Forward]
December 31, 2015	0
Additional accruals	34,000	0
Cash payments	0
Non-cash settlements	(34,000)
Accrued restructuring balance as of December 31, 2016	$ 0	$ 0