Marketable Securities and Fair Value Disclosures - Summary of Marketable securities (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 7,812
Fair Value	7,809
Short-term available-for-sale securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,812	$ 13,778
Gross Unrealized Gains	1
Gross Unrealized Losses	(4)	(16)
Fair Value	7,809	13,762
Short-term available-for-sale securities \| Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,313	13,778
Gross Unrealized Gains	1
Gross Unrealized Losses	(4)	(16)
Fair Value	7,310	13,762
Short-term available-for-sale securities \| Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	499
Fair Value	$ 499
Long-term available-for-sale securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,355
Gross Unrealized Gains		3
Gross Unrealized Losses		(6)
Fair Value		2,352
Long-term available-for-sale securities \| Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost		2,355
Gross Unrealized Gains		3
Gross Unrealized Losses		(6)
Fair Value		$ 2,352

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (aa)
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-Publisher FASB
-Name Accounting Standards Codification
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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Section 45
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-Publisher FASB
-Name Accounting Standards Codification
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