Stock Based Compensation and Employee Benefit Plans - Summary of Stock Option Activity (Detail) In Thousands, except Share data, unless otherwise specified		3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Apr. 16, 2014 USD ($)	Mar. 31, 2015 2014 NPS Corp Plan [Member] USD ($)	Dec. 31, 2014 2014 NPS Corp Plan [Member] USD ($)	Mar. 31, 2015 Mira III Stock Option Awards [Member] CAD	Dec. 31, 2014 Mira III Stock Option Awards [Member] USD ($)	Dec. 31, 2014 Mira III Stock Option Awards [Member] CAD	Mar. 31, 2015 Mira III Stock Option Awards [Member] USD ($)	Apr. 16, 2014 Mira III Stock Option Awards [Member] CAD
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares Outstanding, Beginning balance		2,403,347					35,938
Shares, Granted		14,000
Shares, Exercised		(1,596)		(7,187)
Shares, Canceled		(7,490)
Shares Outstanding, Ending balance		2,408,261	2,403,347		35,938	35,938	35,938
Shares Exercisable - March 31, 2015	367,500	1,123,569					35,938	35,938
Shares vested and expected to vest March 31, 2015		2,263,801					35,938
Weighted-Average Exercise Price, Outstanding, Beginning balance		$ 2.20		3.48
Weighted-Average Exercise Price, Granted		$ 1.84
Weighted-Average Exercise Price, Exercised		$ 1.59		3.48
Weighted-Average Exercise Price, Canceled		$ 2.15
Weighted-Average Exercise Price, Outstanding, Ending balance		$ 2.20	$ 2.20	3.48		3.48
Weighted-Average Exercise Price, Exercisable - March 31, 2015	$ 3.64	$ 2.18		3.48				3.48
Weighted-Average Exercise Price, Shares vested and expected to vest March 31, 2015		$ 2.19		3.48
Average Remaining Weighted-Average Contractual Term (in Years), Outstanding - December 31, 2014		5 years 7 months 13 days	5 years 11 months 19 days	1 month 6 days	3 months 18 days	3 months 18 days
Average Remaining Weighted-Average Contractual Term (in Years), Outstanding - March 31, 2015		5 years 7 months 13 days	5 years 11 months 19 days	1 month 6 days	3 months 18 days	3 months 18 days
Average Remaining Weighted-Average Contractual Term (in Years), Exercisable - March 31, 2015		5 years 1 month 21 days		1 month 6 days
Average Remaining Weighted-Average Contractual Term (in Years), Shares vested and expected to vest March 31, 2015		5 years 7 months 2 days		1 month 6 days
Aggregate Intrinsic Value, Outstanding - December 31, 2014			$ 2,151		$ 0
Aggregate Intrinsic Value, Outstanding - March 31, 2015			2,151		0
Aggregate Intrinsic Value, Exercisable - March 31, 2015		0	0		0		0
Aggregate Intrinsic Value, Shares vested and expected to vest March 31, 2015		$ 0	$ 0		$ 0		$ 0