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)

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (i)

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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

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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-Name Accounting Standards Codification

-Topic 718

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-Paragraph 2

-Subparagraph (j)

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-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

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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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-Name Accounting Standards Codification

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-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)(1)

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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).

+ 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 (c)(2)(iii)(1)

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- Definition

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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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

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

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)-(ii)

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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 SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

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-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 $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Feb. 28, 2014	Jan. 31, 2014	Dec. 31, 2013	May 31, 2013	Mar. 31, 2013	Jan. 31, 2013	Dec. 31, 2012	Jul. 31, 2012	May 31, 2012	Feb. 29, 2012	Jan. 31, 2012	Dec. 31, 2011	Jun. 18, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock reserved for future issuance	26,364			26,364
Outstanding options issued	6,505,664	6,747,303	7,147,303	6,505,664			6,747,303				7,147,303					5,138,486
Proceeds from stock options exercised	$ 1,386,000	$ 956,000	$ 30,000
Total intrinsic value of options	2,600,000	1,400,000	11,000
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			2 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase of shares of restricted common stock				81,702	14,600	16,031	56,683	2,623	5,400	52,018	107,413	15,740
Repurchase of shares of restricted common stock, price per share				$ 5.04	$ 4.40	$ 4.37	$ 4.37	$ 1.65	$ 4.50	$ 4.28	$ 4.19	$ 6.06
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													25,000	43,802	101,500
Restricted Stock \| Non Employee Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period				1 year			1 year				3 years
Share-based payment award granted				66,828			75,272				87,730
Non Vested Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation costs related to non-vested restricted stock outstanding	7,900,000			7,900,000
Expected recognition period	1 year 7 months 13 days
Unvested Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected recognition period	1 year
Share-based payment award granted	66,828	75,272	258,032
Unrecognized stock-based compensation expense related to non-vested restricted stock arrangements	$ 471,000			$ 471,000
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									4,000,000				5,000,000
the "2012 Plan" \| Employees \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	5,112,800			5,112,800
the "2012 Plan" \| Director \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	902,529			902,529
the "2012 Plan" \| Consultants \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options issued	490,334			490,334