Fair Value Measurements (Details) (Recurring, Fair value, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets:
Restricted cash	$ 340ttoo_RestrictedCashFairValueDisclosure	$ 340ttoo_RestrictedCashFairValueDisclosure
Total assets	65,635us-gaap_AssetsFairValueDisclosure	74,189us-gaap_AssetsFairValueDisclosure
Cash
Assets:
Cash and cash equivalents	2,294	10,348
Money market funds
Assets:
Cash and cash equivalents	63,001	63,501
Level 1
Assets:
Restricted cash	340	340
Total assets	65,635	74,189
Level 1 \| Cash
Assets:
Cash and cash equivalents	2,294	10,348
Level 1 \| Money market funds
Assets:
Cash and cash equivalents	$ 63,001	$ 63,501

Fair value portion of cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- 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)

-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

+ Details

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Balance Type:	debit
Period Type:	instant

- Details

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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

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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Balance Type:	debit
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