Basis of Presentation and Summary of Significant Accounting Policies (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) operating_segment	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Loss Contingencies [Line Items]
Cash and cash equivalents	$ 14,918,000	$ 16,963,000	$ 14,918,000	$ 16,963,000	$ 23,273,000	$ 26,487,000
Cash	3,700,000		3,700,000		12,200,000
Money market funds	11,200,000		11,200,000		11,100,000
Restricted cash, current	883,000		883,000		0
Noncurrent restricted cash	783,000		$ 783,000		787,000
Number of operating segments | operating_segment			1
Number of reportable segments | operating_segment			1
Goodwill impairment			$ 0		$ 0
Benefit from income taxes	0	$ (274,000)	15,000	$ 144,000
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Noncurrent restricted cash	$ 700,000		$ 700,000