Loan Payable - Summary of Changes in Carrying Value of Loan Payable (Detail)	3 Months Ended
Mar. 31, 2016 USD ($)
Debt Instrument [Line Items]
Carrying value of loan payable (current) Beginning Balance	$ 1,417,388
Carrying value of loan payable (current) Ending Balance	358,318
Silicon Valley Bank Loan Agreement [Member]
Debt Instrument [Line Items]
Carrying value of loan payable (current) Beginning Balance	1,417,388
Repayment of principal	(1,064,177)
Accretion of discount	5,107
Carrying value of loan payable (current) Ending Balance	$ 358,318

Accretion Of Debt Discount Net Carrying Amount

No definition available.

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Namespace Prefix:	stem_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of the total principal payments made during the annual reporting period.

+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 22
-Article 5

+ Details

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Namespace Prefix:	us-gaap_
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

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of portion of long-term loans payable due within one year or the operating cycle if longer.

+ 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 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: