Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	$ 39,300	$ 0
Marketable securities, noncurrent	400	0
Marketable securities
Available for sale securities in an unrealized loss position	22,900
Available for sale securities, unrealized loss	15
Recurring
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	26,958
Marketable securities, current	39,300
Total assets	69,089	89,713
Recurring \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	23,805
Marketable securities, current	0
Total assets	26,236	89,713
Recurring \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	3,153
Marketable securities, current	39,300
Total assets	42,853	0
Recurring \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0
Marketable securities, current	0
Total assets	0	0
Recurring \| U.S. government agency securities and treasuries
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	24,617
Marketable securities, noncurrent	400
Recurring \| U.S. government agency securities and treasuries \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0
Marketable securities, noncurrent	0
Recurring \| U.S. government agency securities and treasuries \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	24,617
Marketable securities, noncurrent	400
Recurring \| U.S. government agency securities and treasuries \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0
Marketable securities, noncurrent	0
Recurring \| Corporate debt securities
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	14,683
Recurring \| Corporate debt securities \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0
Recurring \| Corporate debt securities \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	14,683
Recurring \| Corporate debt securities \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Marketable securities, current	0
Money market funds \| Recurring
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	23,805	89,713
Money market funds \| Recurring \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	23,805	89,713
Money market funds \| Recurring \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	0
Money market funds \| Recurring \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0	$ 0
U.S. government agency securities and treasuries \| Recurring
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	1,353
U.S. government agency securities and treasuries \| Recurring \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0
U.S. government agency securities and treasuries \| Recurring \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	1,353
U.S. government agency securities and treasuries \| Recurring \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents
Corporate debt securities \| Recurring
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	1,800
Corporate debt securities \| Recurring \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0
Corporate debt securities \| Recurring \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	1,800
Corporate debt securities \| Recurring \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0
Restricted cash \| Recurring
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,431
Restricted cash \| Recurring \| Quoted prices in active markets (Level 1)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	2,431
Restricted cash \| Recurring \| Significant other observable inputs (Level 2)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	0
Restricted cash \| Recurring \| Significant unobservable inputs (Level 3)
Fair value of assets measured at fair value on a recurring basis
Cash and Cash Equivalents	$ 0

Represents the aggregate amortized cost of available for sale investments in an unrealized loss position.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27337-111563

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-Publisher FASB
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- Definition

Amount of investment in debt and equity securities categorized neither as trading securities nor held-to-maturity securities and intended be sold or mature one year or operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
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- Definition

Investments in debt and equity securities which are categorized neither as held-to-maturity nor trading and which are intended to be sold or mature more than one year from the balance sheet date or operating cycle, if longer. Such securities are reported at fair value; unrealized gains (losses) related to Available-for-sale Securities are excluded from earnings and reported in a separate component of shareholders' equity (other comprehensive income), unless the Available-for-sale security is designated as a hedge or is determined to have had an other than temporary decline in fair value below its amortized cost basis. All or a portion of the unrealized holding gain (loss) of an Available-for-sale security that is designated as being hedged in a fair value hedge is recognized in earnings during the period of the hedge, as are other than temporary declines in fair value below the cost basis for investments in equity securities and debt securities that an entity intends to sell or it is more likely than not that it will be required to sell before the recovery of its amortized cost basis. Other than temporary declines in fair value below the cost basis for debt securities categorized as Available-for-sale that an entity does not intend to sell and for which it is not more likely than not that the entity will be required to sell before the recovery of its amortized cost basis are bifurcated into credit losses and losses related to all other factors. Other than temporary declines in fair value below cost basis related to credit losses are recognized in earnings, and losses related to all other factors are recognized in other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Available-for-Sale Securities
-URI http://asc.fasb.org/extlink&oid=6505594

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-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6507016

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