Aggregate number of common shares reserved for future issuance.

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 210.5-02.29)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

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- Definition

The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (j)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3255-108585

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-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

Number of options outstanding, including both vested and non-vested options.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

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Share Based Compensation Arrangement by Share Based Payment Award, Contractual Life

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Stock Repurchased During Period Per Share

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Stock Option Plan - Additional information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended											12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	May. 31, 2015	Dec. 31, 2014	Feb. 28, 2014	Jan. 31, 2014	Dec. 31, 2013	May. 31, 2013	Mar. 31, 2013	Jan. 31, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 18, 2014	May. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	26,364											26,364
Outstanding options issued	3,481,469				6,505,664			6,747,303				3,481,469	6,505,664	6,747,303	7,147,303
Proceeds from stock options exercised												$ 4,568	$ 1,386	$ 956
Total intrinsic value of options												23,800	$ 2,600	$ 1,400
Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															3 years
Contractual terms															10 years
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual terms															10 years
Director \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															3 years
Director \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period															1 year
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of shares of restricted common stock	16,709	7,669			81,702	14,600	16,031	56,683	2,623	5,400	52,018
Repurchase of shares of restricted common stock, price per share	$ 8.31	$ 11.57			$ 5.04	$ 4.40	$ 4.37	$ 4.37	$ 1.65	$ 4.50	$ 4.28
Restricted Stock \| Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years		3 years	3 years
Share-based payment award granted	403,083		50,000	1,000,000
Restricted Stock \| Non Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year				1 year			1 year
Share-based payment award granted	133,305	4,186			66,828			75,272
Non Vested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested restricted stock outstanding	$ 5,300											$ 5,300
Expected recognition period												1 year 6 months 18 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period												1 year 8 months 23 days
Share-based payment award granted												1,590,574	66,828	75,272
Unrecognized stock-based compensation expense related to non-vested restricted stock arrangements	$ 12,100											$ 12,100
the "2012 Plan"
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	9,000,000											9,000,000				5,000,000	4,000,000
the "2012 Plan" \| Employees \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	2,420,801											2,420,801
the "2012 Plan" \| Director \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	927,500											927,500
the "2012 Plan" \| Consultants \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	133,167											133,167