Basis of Presentation and Summary of Significant Accounting Policies (Details)	3 Months Ended			12 Months Ended
	Mar. 31, 2017 USD ($) operating_segment	Dec. 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Cash and cash equivalents	$ 13,923,000	$ 19,240,000	$ 22,163,000	$ 19,240,000	$ 23,273,000
Cash	2,700,000	8,100,000		8,100,000
Money market funds	11,200,000	11,200,000		11,200,000
Noncurrent restricted cash	1,592,000	1,624,000		1,624,000
Impairment charge	$ 0	0
Number of operating segments | operating_segment	1
Number of reportable segments | operating_segment	1
Goodwill impairment	$ 0			0
Provision for income taxes	24,000		$ 11,000
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Noncurrent restricted cash	700,000	800,000		800,000
India
Loss Contingencies [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	$ 900,000	$ 800,000		$ 800,000