Preferred Stock, Common Stock and Stockholders' Equity - Summary of Stock Option Activity (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding beginning balance	1,037,500
Options, Outstanding ending balance	1,275,624	1,037,500
2007 Plan and 2013 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options, Outstanding beginning balance	1,037,500
Options, Granted	941,624
Options, Expired/Forfeited/Exchanged	(703,500)
Options, Outstanding ending balance	1,275,624	1,037,500
Options, Vested and expected to vest at December 31, 2016	1,275,624
Options, Exercisable at December 31, 2016	584,663
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted Average Exercise Price, Outstanding beginning balance	$ 7.19
Weighted Average Exercise Price, Granted	3.26
Weighted Average Exercise Price, Expired/Forfeited/Exchanged	7.65
Weighted Average Exercise Price, Outstanding ending balance	4.04	$ 7.19
Weighted Average Exercise Price, Vested and expected to vest at December 31, 2016	4.04
Weighted Average Exercise Price, Exercisable at December 31, 2016	$ 4.86
Share Based Compensation Arrangement By Share Based Payment Award Options Outstanding, Weighted Average Remaining Contractual Term [Abstract]
Weighted Average Remaining Contractual Term (Years), Outstanding	8 years 4 months 2 days	8 years 15 days
Weighted Average Remaining Contractual Term (Years), Granted	9 years 1 month 13 days
Weighted Average Remaining Contractual Term (Years), Expired/Forfeited/Exchanged	7 years 5 months 16 days
Weighted Average Remaining Contractual Term (Years), Vested and expected to vest at December 31, 2016	8 years 4 months 2 days
Weighted Average Remaining Contractual Term (Years), Exercisable at December 31, 2016	7 years 5 months 1 day
Share Based Compensation Arrangement by Share Based Payment Award Options Outstanding, Aggregate Intrinsic Value [Abstract]
Aggregate Intrinsic Value, Outstanding beginning balance	$ 342,200
Aggregate Intrinsic Value, Outstanding ending balance	191,160	$ 342,200
Aggregate Intrinsic Value, Vested and expected to vest at December 31, 2016	191,160
Aggregate Intrinsic Value, Exercisable at December 31, 2016	$ 191,160