Stock Based Compensation - Stock-Based Compensation Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock-based compensation expense
Stock-based compensation expense	$ 4,053,000	$ 1,653,000	$ 578,000
Stock based compensation expense included cost of product revenue	48,000
Stock based compensation expense included capitalized of inventory	67,000
Total unrecognized compensation costs related to non-vested stock options	$ 11,300,000
Remaining weighted-average period that unrecognized compensation costs are expected to be recognized	2 years 10 months 28 days
Research and development
Stock-based compensation expense
Stock-based compensation expense	$ 1,213,000	501,000	169,000
Selling, general and administrative
Stock-based compensation expense
Stock-based compensation expense	$ 2,840,000	$ 1,152,000	$ 409,000