Statements of Redeemable Convertible Preferred Stock and Stockholders' Equity (Deficit) - USD ($)	Global Foundries Additional Paid-In Capital	Global Foundries	Common Stock Initial Public Offering	Common Stock Private Placement	Common Stock	Additional Paid-In Capital Initial Public Offering	Additional Paid-In Capital Private Placement	Additional Paid-In Capital	Accumulated Deficit	Initial Public Offering	Private Placement	Total
Balance at Dec. 31, 2014								$ 7,120,000	$ (61,548,000)			$ (54,428,000)
Balance (in shares) at Dec. 31, 2014					3,013,723
Increase (Decrease) in Stockholders' Equity
Issuance of common stock (in shares)					1,558
Issuance of common stock upon exercise of stock options								4,000				4,000
Compensation expense related to vesting of common stock issued to GLOBALFOUNDRIES								1,761,000				1,761,000
Stock-based compensation expense								416,000				416,000
Net loss					$ 0			0	(18,183,000)			(18,183,000)
Balance at Dec. 31, 2015								9,301,000	(79,731,000)			(70,430,000)
Balance (in shares) at Dec. 31, 2015					3,015,281
Increase (Decrease) in Stockholders' Equity
Conversion of redeemable convertible preferred stock to common stock								64,642,000				64,642,000
Conversion of redeemable convertible preferred stock to common stock (in shares)					2,486,199
Conversion of convertible promissory notes to common stock								8,634,000				8,634,000
Conversion of convertible promissory notes to common stock (in shares)					1,361,009
Reclassification of redeemable convertible preferred stock warrant liability to additional paid in capital								65,000				65,000
Issuance of common stock			$ 1,000			$ 33,863,000	$ 4,650,000			$ 33,864,000	$ 4,650,000
Issuance of common stock (in shares)			5,000,000	625,000	10,639
Issuance of common stock upon exercise of stock options								48,000				$ 48,000
Issuance of common stock upon exercise of stock options (in shares)												10,639
Compensation expense related to vesting of common stock issued to GLOBALFOUNDRIES	$ 965,000	$ 965,000
Stock-based compensation expense								1,141,000				$ 1,141,000
Net loss									(16,708,000)			(16,708,000)
Balance at Dec. 31, 2016					$ 1,000			123,309,000	(96,439,000)			26,871,000
Balance (in shares) at Dec. 31, 2016					12,498,128
Increase (Decrease) in Stockholders' Equity
Issuance of common stock upon exercise of stock options								1,337,000				$ 1,337,000
Issuance of common stock upon exercise of stock options (in shares)					281,483							281,483
Issuance of common stock under Employee Stock Purchase Plan								256,000				$ 256,000
Issuance of common stock under Employee Stock Purchase Plan (in shares)					37,590
Compensation expense related to vesting of common stock issued to GLOBALFOUNDRIES								1,472,000				1,472,000
Stock-based compensation expense								2,048,000				2,048,000
Net loss									(21,100,000)			(21,100,000)
Balance at Dec. 31, 2017					$ 1,000			$ 128,422,000	$ (117,539,000)			$ 10,884,000
Balance (in shares) at Dec. 31, 2017					12,817,201