Income Taxes - Deferred Income Taxes Components (Details) (USD $) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net operating loss carryforward	$ 28,584	$ 15,492
Property & equipment	339	77
Inventory	864	620
Stock options	5,208	3,644
Intangible assets, definite-lived	333	421
General business credit	1,915	885
Deferred revenue	372	380
Other	187	0
Charitable contribution	18	13
Valuation allowance	(37,820)	(21,532)
Deferred tax assets	$ 0	$ 0