XML 65 R21.htm IDEA: XBRL DOCUMENT v2.4.0.8

Fair value (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2013 Fair value measurements on a recurring basis Level 1	Jun. 30, 2013 Fair value measurements on a recurring basis Level 2	Jun. 30, 2013 Fair value measurements on a recurring basis Cash and money market funds Level 1	Jun. 30, 2013 Fair value measurements on a recurring basis Corporate obligations (including commercial paper) Level 2	Jun. 30, 2013 Fair value measurements on a recurring basis Short-term investments Level 3	Dec. 31, 2012 Fair value measurements on a recurring basis Short-term investments Level 3
Assets:
Total			$ 28,193	$ 26,152	$ 28,193	$ 26,152	$ 0	$ 0
Transfers of assets from Level 1 to Level 2	0	0
Transfers of assets from Level 2 to Level 1	0	0
Transfers of liabilities from Level 1 to Level 2	0	0
Transfers of liabilities from Level 2 to Level 1	$ 0	$ 0

X

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

No definition available.

+ Details

Name:	ovas_FairValueAssetsLevel1ToLevel2TransferAmount
Namespace Prefix:	ovas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount of transfers of assets measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

No definition available.

+ Details

Name:	ovas_FairValueAssetsLevel2ToLevel1TransferAmount
Namespace Prefix:	ovas_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

No definition available.

+ Details

Name:	ovas_FairValueLiabilitiesLevel1ToLevel2TransferAmount
Namespace Prefix:	ovas_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 2 of the fair value hierarchy into Level 1.

+ References

No definition available.

+ Details

Name:	ovas_FairValueLiabilitiesLevel2ToLevel1TransferAmount
Namespace Prefix:	ovas_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

+ 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=7578670&loc=d3e19207-110258

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration