Stock-Based Compensation - Stock Options - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions																			12 Months Ended
	May. 31, 2016	Nov. 30, 2015	Jun. 15, 2015	May. 31, 2015	May. 15, 2015	Feb. 28, 2015	Feb. 11, 2015	Nov. 30, 2014	Nov. 10, 2014	Nov. 05, 2014	Aug. 31, 2014	Aug. 14, 2014	May. 31, 2014	May. 16, 2014	May. 09, 2014	Apr. 21, 2014	Feb. 28, 2014	Feb. 12, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																			10 years
Exercisable period of options																			4 years
Options purchased shares, grants during the period																			222,625	654,000	467,500
Award date exercise price per share granted to certain employees																			$ 6.57	$ 5.63	$ 4.49
Common stock available for grants																			1,776,903
Unrecognized compensation expense related to stock options																			$ 2.0
Expected weighted average period																			1 year 8 months 12 days
February 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																	10 years
Restricted stock, vesting percentage																	25.00%
Restricted stock, vesting date																	Feb. 28, 2015
Restricted stock, vesting period																			12 quarters
August 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options								10 years
Options purchased shares, grants during the period												19,500
Award date exercise price per share granted to certain employees												$ 4.88
Restricted stock, vesting percentage								6.25%
Restricted stock, vesting date								Nov. 30, 2014
Restricted stock, vesting period																			15 quarters
November 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options		10 years
Options purchased shares, grants during the period									90,000
Award date exercise price per share granted to certain employees									$ 5.58
Restricted stock, vesting percentage		25.00%
Restricted stock, vesting period																			12 quarters
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period																			222,625
Stock Options [Member] | February 2016 Award date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting percentage							25.00%
Restricted stock, vesting period																			12 quarters
Stock Options [Member] | May 2015 Award Date [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting percentage				25.00%
Stock Options [Member] | November 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options								10 years
Options purchased shares, grants during the period										10,000
Award date exercise price per share granted to certain employees										$ 5.45
Restricted stock, vesting percentage								6.25%
Restricted stock, vesting period																			15 quarters
Non Employee Director [Member] | Commencement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercisable period of options																			48 months
Options purchased shares, grants during the period																			50,000
Non Employee Director [Member] | Post Annual Meeting [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																			10 years
Options purchased shares, grants during the period																			10,000
Non Employee Director [Member] | Stock Options [Member] | May 2015 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period					70,000
Award date exercise price per share granted to certain employees					$ 6.13
Restricted stock, vesting period																			3 quarters
Expiration of options				May 15, 2025
Non Executive Employee [Member] | Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period							122,625
Award date exercise price per share granted to certain employees							$ 6.90
Expiration of options																			Feb. 11, 2025
Non Executive Employee [Member] | Stock Options [Member] | February 2015 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting date						Feb. 28, 2015
Restricted stock, vesting period																			15 quarters
Non Executive Employee [Member] | Stock Options [Member] | February 2015 Award Date [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting percentage						6.25%
Non Executive Employee [Member] | Stock Options [Member] | February 2016 Award date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting date																			Feb. 28, 2016
Non Executive Employee [Member] | Stock Options [Member] | June 2015 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period			30,000
Award date exercise price per share granted to certain employees			$ 6.24
Restricted stock, vesting period																			12 quarters
Non Executive Employee [Member] | Stock Options [Member] | June 2015 Award Date [Member] | Scenario, Forecast [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration of options	Jun. 15, 2025
Non Executive Employee [Member] | Stock Options [Member] | June 2015 Award Date [Member] | Scenario, Forecast [Member] | Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock, vesting percentage	25.00%
Company Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period																				654,000
Company Employees [Member] | February 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period																		70,000
Award date exercise price per share granted to certain employees																		$ 5.81
Company Employees [Member] | May 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period															169,500
Award date exercise price per share granted to certain employees															$ 4.95
Restricted stock, vesting percentage											6.25%
Restricted stock, vesting date											Aug. 31, 2014
Company Employees [Member] | Stock Options [Member] | May 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options				10 years
Restricted stock, vesting percentage				25.00%
Restricted stock, vesting date				May 31, 2015
Restricted stock, vesting period				15 quarters															12 quarters
Executive Officers [Member] | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period																					467,500
Executive Officers [Member] | April 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options													10 years
Options purchased shares, grants during the period																225,000
Award date exercise price per share granted to certain employees																$ 6.38
Restricted stock, vesting percentage													6.25%
Restricted stock, vesting period																			15 quarters
Executive Officers [Member] | February 2013 Award Date [Member | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																					10 years
Award date exercise price per share granted to certain employees																					$ 4.48
Restricted stock, vesting percentage																					25.00%
Restricted stock, vesting date																					Feb. 28, 2014
Restricted stock, vesting period																			12 quarters
Common stock available for grants																					5,000
Executive Officers [Member] | March 2013 Award Date [Member] | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																					10 years
Options purchased shares, grants during the period																					342,500
Award date exercise price per share granted to certain employees																					$ 4.69
Restricted stock, vesting percentage																					6.25%
Restricted stock, vesting date																					May 31, 2013
Restricted stock, vesting period																			15 quarters
Executive Officers [Member] | May 2013 Award Date [Member] | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																					10 years
Restricted stock, vesting percentage																					25.00%
Restricted stock, vesting date																					May 31, 2014
Restricted stock, vesting period																			12 quarters
Executive Officers [Member] | November 2013 Award Date [Member] | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options																					10 years
Options purchased shares, grants during the period																					50,000
Award date exercise price per share granted to certain employees																					$ 4.10
Restricted stock, vesting percentage																					6.25%
Restricted stock, vesting date																					Nov. 03, 2013
Restricted stock, vesting period																			15 quarters
Board of Directors [Member] | May 2014 Award Date [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum term of options				10 years
Options purchased shares, grants during the period														70,000
Award date exercise price per share granted to certain employees														$ 4.99
Restricted stock, vesting percentage				25.00%
Restricted stock, vesting date				May 31, 2015
Restricted stock, vesting period																			12 quarters
Board of Directors [Member] | May 2013 Award Date [Member] | 2013 Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options purchased shares, grants during the period																					70,000