Basis of Presentation and Summary of Significant Accounting Policies (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) operating_segment	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items]
Cash and cash equivalents	$ 28,817,000	$ 22,352,000	$ 28,817,000	$ 22,352,000	$ 19,240,000	$ 23,273,000
Cash	18,100,000		18,100,000		8,000,000
Money market funds	10,700,000		10,700,000		11,200,000
Noncurrent restricted cash	1,576,000		1,576,000		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
Benefit from income taxes	42,000	$ 26,000	18,000	$ 15,000
Financial Standby Letter of Credit [Member]
Loss Contingencies [Line Items]
Noncurrent restricted cash	700,000		700,000		800,000
India
Loss Contingencies [Line Items]
Restricted Cash and Cash Equivalents, Noncurrent	$ 900,000		$ 900,000		$ 800,000