Shareholders' Equity - Schedule of Stock-Based Compensation Expense (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Costs and Expenses
Total employee stock-based compensation expense	$ 1,029	$ 616
Impact on basic and diluted net income (loss) per common share	$ (0.07)	$ 0.04
Research and Development [Member]
Costs and Expenses
Total employee stock-based compensation expense	$ 522	$ 197
General and Administrative [Member]
Costs and Expenses
Total employee stock-based compensation expense	$ 507	$ 419