Consolidated Statements of Operations and Comprehensive Loss (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Sales	$ 401	$ 1,431
Operating Expenses
Cost of goods sold	1,095	4,810
Research and development	27,944	12,700
Sales and marketing	1,727	1,943
General and administrative	6,244	4,221
Impairment loss on property and equipment		450
Merger expenses		2,911
Total Operating Expenses	37,010	27,035
Operating Loss	(36,609)	(25,604)
Other Expense
Remeasurement of fair value of preferred stock warrant liability		(1,800)
Interest expense, net	(1,043)	(954)
Total Other Expense, net	(1,043)	(2,754)
Net Loss	(37,652)	(28,358)
Other comprehensive income (loss)	0	0
Comprehensive loss	$ (37,652)	$ (28,358)
Net loss per share - basic and diluted	$ (0.64)	$ (2.23)
Weighted average common shares outstanding - basic and diluted	58,714	12,731