Stock-Based Compensation - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,038	$ 1,239	$ 1,150
Share Based Compensation Stock Options | Equity awards for non-employees issued for services | Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0	3	4
Share Based Compensation Stock Options | Equity awards for non-employees issued for services | Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	0	0	101
Share Based Compensation Stock Options | Stock-based compensation expense for employees | Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	158	38	32
Share Based Compensation Stock Options | Stock-based compensation expense for employees | Selling, General and Administrative Expenses
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,880	$ 1,198	$ 1,013