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

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=25499696&loc=d3e19207-110258

+ Details

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

- Details

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

- Details

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

- Definition

Amount of 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

+ References

+ Details

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

- Definition

Investments which are intended to be sold in the short term (usually less than one year or the normal operating cycle, whichever is longer) including trading securities, available-for-sale securities, held-to-maturity securities, and other short-term investments not otherwise listed in the existing taxonomy.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.2)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Subparagraph g

-Article 7

+ Details

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

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Fair Value Measurement of Assets and Liabilities - Summary of Company's Financial Instruments, Fair Value on a Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Measurements, Recurring
Cash equivalents
Total cash equivalents	$ 2,114	$ 487
Available-for-sale:
Total short-term marketable securities		19,178
Total long-term marketable securities		3,443
Total financial assets		23,108
Fair Value, Measurements, Recurring \| Government agency securities
Available-for-sale:
Total short-term marketable securities		2,351
Fair Value, Measurements, Recurring \| Municipal bonds
Available-for-sale:
Total short-term marketable securities		2,829
Fair Value, Measurements, Recurring \| Certificates of deposit
Available-for-sale:
Total short-term marketable securities		3,360
Total long-term marketable securities		1,300
Fair Value, Measurements, Recurring \| Corporate debentures / bonds
Available-for-sale:
Total short-term marketable securities		10,638
Total long-term marketable securities		2,143
Fair Value, Measurements, Recurring \| Money market funds
Cash equivalents
Total cash equivalents	1,134
Fair Value, Measurements, Recurring \| US Treasury securities
Cash equivalents
Total cash equivalents		487
Fair Value, Measurements, Recurring \| Certificates of deposit
Cash equivalents
Total cash equivalents	980
Level 1
Cash equivalents
Total cash equivalents	1,134	0
Available-for-sale:
Total short-term marketable securities		0
Total long-term marketable securities		0
Total financial assets		0
Level 1 \| Government agency securities
Available-for-sale:
Total short-term marketable securities		0
Level 1 \| Municipal bonds
Available-for-sale:
Total short-term marketable securities		0
Level 1 \| Certificates of deposit
Available-for-sale:
Total short-term marketable securities		0
Total long-term marketable securities		0
Level 1 \| Corporate debentures / bonds
Available-for-sale:
Total short-term marketable securities		0
Total long-term marketable securities		0
Level 1 \| Money market funds
Cash equivalents
Total cash equivalents	1,134
Level 1 \| US Treasury securities
Cash equivalents
Total cash equivalents		0
Level 1 \| Certificates of deposit
Cash equivalents
Total cash equivalents	0
Level 2
Cash equivalents
Total cash equivalents	980	487
Available-for-sale:
Total short-term marketable securities		19,178
Total long-term marketable securities		3,443
Total financial assets		23,108
Level 2 \| Government agency securities
Available-for-sale:
Total short-term marketable securities		2,351
Level 2 \| Municipal bonds
Available-for-sale:
Total short-term marketable securities		2,829
Level 2 \| Certificates of deposit
Available-for-sale:
Total short-term marketable securities		3,360
Total long-term marketable securities		1,300
Level 2 \| Corporate debentures / bonds
Available-for-sale:
Total short-term marketable securities		10,638
Total long-term marketable securities		2,143
Level 2 \| Money market funds
Cash equivalents
Total cash equivalents	0
Level 2 \| US Treasury securities
Cash equivalents
Total cash equivalents		487
Level 2 \| Certificates of deposit
Cash equivalents
Total cash equivalents	$ 980