Significant Customers and Concentrations of Risk - Summary of Significant Customers Comprising 10% or More of Total Revenue (Detail) - USD ($)		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Concentration Risk [Line Items]
Total revenues		$ 14,196,121	$ 13,478,763	$ 12,228,390	$ 12,318,772	$ 11,803,920	$ 11,085,752	$ 14,420,391	$ 8,348,037	$ 52,222,046	$ 45,658,100	$ 26,501,665
Teva [Member]
Concentration Risk [Line Items]
Total revenues										24,941,371	17,714,823	8,682,384
Ferring [Member]
Concentration Risk [Line Items]
Total revenues										6,282,974	6,116,642	4,760,084
McKesson [Member]
Concentration Risk [Line Items]
Total revenues	[1]									$ 7,599,905	6,837,047	3,460,000
LEO Pharma [Member]
Concentration Risk [Line Items]
Total revenues											$ 6,000,000	$ 3,428,571

[1] Represents estimated revenue, net of deferrals, based on OTREXUP® shipments to the distributor.