Debt and Related Warrants - Summary of 2015 Credit Facility (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
2015 Credit Facility
Net carrying value of debt, Current Portion	$ 3,884	$ 1,175
Net carrying value of debt, Long-term debt	4,218	6,739
2015 Credit Facility
2015 Credit Facility
Debt, including end of term fee, Current Portion	4,054	970
Less: discount attributable to warrants, end of term fee and debt issuance cost, Current Portion	(177)
Net carrying value of debt, Current Portion	3,877	970
Debt, including end of term fee, Long-term debt	4,301	7,210
Less: discount attributable to warrants, end of term fee and debt issuance cost, Long-term debt	(83)	(471)
Net carrying value of debt, Long-term debt	4,218	6,739
Debt, including end of term fee, Total	8,355	8,180
Less: discount attributable to warrants, end of term fee and debt issuance cost, Total	(260)	(471)
Net carrying value of debt, Total	$ 8,095	$ 7,709

Amount of unamortized (discount) premium, debt issuance costs and end of term fee, current.

No definition available.

Name:	mram_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsCurrent
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of unamortized (discount) premium, debt issuance costs and end of term fee, noncurrent.

+ References

No definition available.

+ Details

Name:	mram_DebtInstrumentUnamortizedDiscountPremiumAndDebtIssuanceCostsNoncurrent
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Long-term debt before unamortized (discount) premium, debt issuance costs and end of term fee, current.

+ References

No definition available.

+ Details

Name:	mram_LongTermDebtCurrentGross
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long-term debt before unamortized (discount) premium, debt issuance costs and end of term fee.

+ References

No definition available.

+ Details

Name:	mram_LongTermDebtGross
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Long-term debt before unamortized (discount) premium, debt issuance costs and end of term fee, noncurrent.

+ References

No definition available.

+ Details

Name:	mram_LongTermDebtNoncurrentGross
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of unamortized (discount) premium, debt issuance costs and end of term fee

+ References

No definition available.

+ Details

Name:	mram_UnamortizedDiscountPremiumAndDebtIssuanceCostsAndEndOfTermFee
Namespace Prefix:	mram_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LongTermDebtNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_CreditFacilityAxis=mram_AresVentureFinanceCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: