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Marketable Securities and Fair Value Disclosures - Summary of Marketable securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 6,911
Fair Value	6,906
Short-term available-for-sale securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,911	$ 13,778
Gross Unrealized Gains	1
Gross Unrealized Losses	(6)	(16)
Fair Value	6,906	13,762
Short-term available-for-sale securities | Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	6,413	13,778
Gross Unrealized Gains	1
Gross Unrealized Losses	(6)	(16)
Fair Value	6,408	13,762
Short-term available-for-sale securities | Commercial paper
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	498
Fair Value	$ 498
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

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