Share-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Jun. 30, 2012	May 11, 2011	Jul. 08, 2013	Mar. 12, 2013	Sep. 04, 2012	Nov. 12, 2013	Apr. 30, 2014	Apr. 30, 2013	Aug. 23, 2012	Aug. 08, 2013	Nov. 16, 2009
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option Granted	230,000
Restricted Stock Number of Shares Granted	950,000
Outstanding Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Remaining shares reserved for issuance	3,664,024											1,800,000
Additional shares reserved for grant		3,000,000	2,400,000
Stock Option [Member] | Chief Operating Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period				3 years	3 years	2 years
Option Exercise Price				$ 7.33	$ 4.51	$ 3.51
Expiration date of option				Jul. 08, 2018	Mar. 12, 2018	Sep. 04, 2019
Option Granted				300,000	100,000	500,000
Option expiration two year from grant date						250,000
Option expiration one year from grant date						250,000
Options granted, vesting description				The option has an exercise price of $7.33 per share, expires on July 8, 2018 and vests over three years as follows: one third on the one (1) year anniversary of the date of grant, one third on the two (2) year anniversary of the date of grant and one third on the three (3) year anniversary of the date of grant.	The option has an exercise price of $4.51 per share, expires on March 12, 2018 and vests over three years as follows: one third on the one (1) year anniversary of the date of grant, one third on the two (2) year anniversary of the date of grant and one third on the three (3) year anniversary of the date of grant.
Stock Option [Member] | Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period							3 years
Option Exercise Price							$ 8.01
Expiration date of option							Nov. 12, 2020
Option Granted							300,000
Options granted, vesting description	Both option grants have an exercise price of $8.01 per share, expire on November 12, 2020 and vest over three years as follows: one third on the one (1) year anniversary of the date of grant, one third on the two (2) year anniversary of the date of grant and one third on the three (3) year anniversary of the date of grant.
Stock Option [Member] | Chief Administrative Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period							3 years
Option Exercise Price							$ 8.01
Expiration date of option							Nov. 12, 2020
Option Granted							200,000
Options granted, vesting description	Both option grants have an exercise price of $8.01 per share, expire on November 12, 2020 and vest over three years as follows: one third on the one (1) year anniversary of the date of grant, one third on the two (2) year anniversary of the date of grant and one third on the three (3) year anniversary of the date of grant.
Stock Option [Member] | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option awards, expiration period	5 years
Vested and non-vested stock awards, vesting service period	1 year
Stock Option [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock option awards, expiration period	7 years
Vested and non-vested stock awards, vesting service period	3 years
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period	3 years
Restricted Stock [Member] | Chief Operating Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period										2 years
Price of performance-based restricted common stock								$ 12.88	$ 4.88	$ 3.37
Restricted Stock Number of Shares Granted								250,000	250,000	650,000
Cumulated stock vests								Dec. 31, 2014	Apr. 07, 2014
Restricted Stock [Member] | Chief Operating Officer [Member] | January One Two Thousand Thirteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on first anniversary of issue date										38.50%
Restricted Stock [Member] | Chief Operating Officer [Member] | January One Two Thousand Fourteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on second anniversary of issue date										77.00%
Restricted Stock [Member] | Chief Operating Officer [Member] | December Thirty One Two Thousand Fourteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on third anniversary of issue date										100.00%
Restricted Stock [Member] | Chief Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Price of performance-based restricted common stock								$ 12.88	$ 4.88
Restricted Stock Number of Shares Granted								500,000	500,000
Cumulated stock vests								Apr. 07, 2015	Apr. 07, 2014
Restricted Stock [Member] | Chief Administrative Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period								2 years
Price of performance-based restricted common stock								$ 12.88	$ 4.88
Restricted Stock Number of Shares Granted								200,000	100,000
Cumulated stock vests									Apr. 07, 2014
Restricted Stock [Member] | Chief Administrative Officer [Member] | December One Two Thousand Fourteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on first anniversary of issue date								50.00%
Restricted Stock [Member] | Chief Administrative Officer [Member] | December One Two Thousand Fifteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on second anniversary of issue date								50.00%
Restricted Stock [Member] | Chief Financial Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vested and non-vested stock awards, vesting service period											2 years
Price of performance-based restricted common stock											$ 8.55
Restricted Stock Number of Shares Granted											150,000
Restricted Stock [Member] | Chief Financial Officer [Member] | October One Two Thousand Fourteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on first anniversary of issue date											50.00%
Restricted Stock [Member] | Chief Financial Officer [Member] | October One Two Thousand Fifteen [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage on second anniversary of issue date											50.00%