Commitments and Contingencies (Details) $ in Thousands	1 Months Ended			12 Months Ended
	Oct. 31, 2017 ft²	Mar. 31, 2017 ft²	Jan. 31, 2017 ft²	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Minimum rental commitments
2018				$ 1,536
2019				1,645
2020				833
2021				766
2022				46
Total minimum lease payments				4,826
Total rent expense				$ 1,400	$ 1,500	$ 1,400
Arizona manufacturing facility | Freescale
Minimum rental commitments
Period to cancel lease upon notice				24 months
Office and Laboratory Space | Freescale
Minimum rental commitments
Term of lease (in years)			5 years
Number of rent free months	11 months
Additional area of operating lease | ft²	17,951	10,023	6,560