Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Accrued expenses and other liabilities:
Accrued employee compensation and benefits	$ 2,470	$ 2,703
Other liabilities	2,372	1,686
Accrued expenses and other liabilities	6,982	5,873
OTREXUP [Member]
Accrued expenses and other liabilities:
OTREXUP® product returns and sales allowances	$ 2,140	$ 1,484