Fair Value Measurements - Summary of Cash, Cash Equivalents and Short-Term Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash, amortized cost and estimated fair value	$ 1,328
Restricted cash, amortized cost and estimated fair value	272	$ 272
Cash equivalents, Estimated Fair Value	19,700
Cash and cash equivalents, Amortized Cost	19,696
Cash and cash equivalents, Gross Unrealized Gains	4
Amortized Cost	12,757
Gross Unrealized Losses	(2)
Estimated Fair Value	12,755
Money market securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Restricted cash, amortized cost and estimated fair value	272
Cash equivalents, Amortized Cost	8,365
Cash equivalents, Estimated Fair Value	8,365
Government securities [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Cash equivalents, Amortized Cost	10,003
Cash equivalents, Gross Unrealized Gains	4
Cash equivalents, Estimated Fair Value	10,007
Corporate bonds and commercial paper [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Amortized Cost	12,757
Gross Unrealized Losses	(2)
Estimated Fair Value	$ 12,755

Cash and cash equivalents accumulated gross unrealized gain before tax.

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- Definition

Cash and cash equivalents amortized cost basis.

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Cash equivalents accumulated gross unrealized gain before tax.

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- Definition

Cash equivalents amortized cost basis.

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- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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- Definition

This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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- Definition

Amount of investments in debt securities classified as available-for-sale, expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount 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. 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
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-URI http://asc.fasb.org/extlink&oid=6506951

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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
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-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Cash and equivalents whose use in whole or in part is restricted for the long-term, generally by contractual agreements or regulatory requirements.

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-Publisher FASB
-Name Accounting Standards Codification
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