Basis of Presentation and Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) operating_segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Investments, Noncurrent	$ 1,624,000	$ 1,624,000	$ 1,624,000	$ 787,000
Advertising
Advertising Expense		500,000		300,000	$ 300,000
Cash, Cash Equivalents and Marketable Securities [Abstract]
Cash and cash equivalents	19,240,000	19,240,000	19,240,000	23,273,000	26,487,000	$ 22,130,000
Cash	8,100,000	8,100,000	8,100,000	12,153,000
Money market funds	$ 11,200,000	11,200,000	$ 11,200,000	11,100,000
Intangible Assets, Net (Excluding Goodwill) [Abstract]
Impairment of laboratory equipment					1,800,000
Number of operating segments	1		1
Goodwill impairment		0		0	$ 0
India
Cash, Cash Equivalents and Marketable Securities [Abstract]
Restricted cash	$ 800,000	800,000	$ 800,000
Collateral Pledged
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Investments, Noncurrent				$ 800,000
Cash, Cash Equivalents and Marketable Securities [Abstract]
Restricted cash	$ 800,000	$ 800,000	$ 800,000