Related Party Transactions (Details)					3 Months Ended				6 Months Ended		10 Months Ended	12 Months Ended
	Aug. 21, 2016 shares	Oct. 21, 2014 $ / shares shares	Oct. 17, 2014	Oct. 14, 2014	Jun. 30, 2017 USD ($) $ / shares shares	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2017 USD ($) item $ / shares shares	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) $ / shares shares	Dec. 31, 2016 USD ($) $ / shares	Aug. 31, 2016 USD ($) item
Related Party Transactions
Loss on extinguishment of debt					$ (246,000)				$ (246,000)
Amounts due to related parties					1,392,000				1,392,000		$ 1,392,000	$ 1,359,000
Research and development expense					6,427,000		$ 6,094,000		12,816,000	$ 11,231,000
Non-cash compensation expense (income)									716,000	1,442,000
Due from related party					550,000				550,000		550,000	486,000
Freescale
Related Party Transactions
Amounts due to related parties					420,000				420,000		420,000	380,000
Rent paid					377,000		263,000		666,000	520,000
Processing costs capitalized in inventory						$ 1,200,000	591,000		1,600,000	1,300,000
Related party sales					627,000		0		1,200,000	735,000
Due from related party					526,000				526,000		526,000	486,000
Freescale | Wafers
Related Party Transactions
Product purchased which is included in inventory					223,000				391,000
Joint Development Agreement | Global Foundries
Related Party Transactions
Amounts due to related parties					1,000,000				1,000,000		1,000,000	979,000
Purchase of research and development equipment					262,000							0
Research and development expense					1,400,000		1,100,000		$ 3,200,000	2,000,000
Agreement Term			4 years	4 years
Period to Repurchase Shares		1 year
Period of possession of exclusive right to manufacture after qualification of device			3 years
Period of possession of exclusive right to manufacture after completion of device development work			4 years
Number of milestones | item													3
First milestone payment due per the agreement													$ 569,000
Second milestone payment due per the agreement													650,000
Third milestone payment due per the agreement													$ 406,000
Number of milestones achieved | item									2
Milestone revenue					650,000			$ 0	$ 1,200,000	0
Due from related party					$ 24,000				$ 24,000		$ 24,000	$ 0
Joint Development Agreement | Global Foundries | Common Stock
Related Party Transactions
Number of shares sold | shares		461,538
Shares sold, price per share | $ / shares		$ 0.00026
Number of shares of common stock, vested | shares	211,538										96,154
Number of shares of common stock, unvested | shares					153,846				153,846		153,846
Estimated fair value of common stock per share | $ / shares					$ 19.98				$ 19.98		$ 19.98	$ 8.29
Joint Development Agreement | Global Foundries | Research and Development
Related Party Transactions
Non-cash compensation expense (income)					$ 461,000		$ 922,000		$ 716,000	$ 1,400,000
Joint Development Agreement | Global Foundries | Series B Redeemable Convertible Preferred Stock
Related Party Transactions
Number of shares sold | shares		192,307
Shares sold, price per share | $ / shares		$ 26.00