Selected Balance Sheet Components - Amortization Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets, net
Amortization expense	$ 300	$ 300	$ 200
Commercial rights
Intangible assets, net
Gross amount	0	3,360
Accumulated amortization	0	(443)
Intangible assets	$ 0	$ 2,917