XML 62 R51.htm IDEA: XBRL DOCUMENT
v3.19.2

Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands |  |  |  |  | 3 Months Ended
--- | --- | --- | --- | --- | ---
May 22, 2019 | May 14, 2019 | May 13, 2019 | May 10, 2019 | Mar. 31, 2019
2019 Employee Stock Purchase Plan |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Common stock reserved for issuance description |  |  |  |  | Additionally, the number of shares of common stock reserved for issuance under the 2019 Employee Stock Purchase Plan will automatically increase on January 1 of each calendar year for 10 years, starting January 1, 2020, and ending on, and including, January 1, 2029, in an amount equal to the lesser of 1% of the total number of shares of capital stock outstanding on December 31st of the prior calendar year, and (ii) 500,000 shares, unless the board of directors or compensation committee determines prior to such date that there will be a lesser increase, or no increase.
2019 Plan |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Common stock reserved for issuance description |  |  |  |  | 1,885,039 shares of common stock are reserved for future issuance under the 2019 Equity Incentive Plan, plus the number of shares subject to outstanding stock options or other stock awards that were granted under the Option Plan that are forfeited, terminated, expire or are otherwise not issued. Additionally, the number of shares of common stock reserved for issuance under the 2019 Equity Incentive Plan will automatically increase on January 1 of each calendar year for 10 years, starting January 1, 2020 and ending on and including January 1, 2029, in an amount equal to 5% of the total number of shares of capital stock outstanding on December 31 of the prior calendar year, unless the board of directors or compensation committee determines prior to the date of increase that there will be a lesser increase, or no increase.
Subsequent Event |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
IPO closing date |  | May 14, 2019 |  |  |
Subsequent Event | 2019 Employee Stock Purchase Plan |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Common stock, number of shares available for sale |  | 337,007 |  |  |
Period in which reserved shares will increase annually |  | 10 years |  |  |
Increase in common stock reserved for issuance as a percentage of total number of shares of capital stock outstanding on the last day of the prior calendar year |  | 1.00% |  |  |
Increase In common stock reserved for issuance of number of shares of capital stock outstanding on last day of prior calendar year |  | 500,000 |  |  |
Subsequent Event | 2019 Plan |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Common stock, number of shares available for sale |  | 1,885,039 |  |  |
Period in which reserved shares will increase annually |  | 10 years |  |  |
Increase in common stock reserved for issuance as a percentage of total number of shares of capital stock outstanding on the last day of the prior calendar year |  | 5.00% |  |  |
Common Stock |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued and sold |  |  |  |  | 227,628
Common Stock | Subsequent Event |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued upon exercise of warrants |  |  |  | 155,338 |
Proceeds from issuance of shares upon exercise of warrants |  |  |  | $ 23 |
Common Stock | Subsequent Event | Chief Executive Officer |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Restricted stock award, fully vested shares |  |  | 383,197 |  |
Restricted stock award, net shares issued |  |  | 210,758 |  |
Restricted stock award, shares withheld to satisfy tax obligations |  |  | 172,439 |  |
Common Stock | IPO | Subsequent Event |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued and sold | 505,714 | 3,571,429 |  |  |
Shares issued and sold, price per share | $ 11.00 | $ 11.00 |  |  |
Net proceeds from issuance of IPO | $ 37,606 |  |  |  |
Underwriting discounts and commissions | 3,139 |  |  |  |
Offering expenses paid | $ 4,102 |  |  |  |
Common Stock | Over-Allotment | Subsequent Event |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |
Shares issued and sold | 30,000 |  |  |  |
Shares issued and sold, price per share | $ 11.00 |  |  |  |

X
- Definition Common stock capital shares reserved for future issuance term of annual increase. + References No definition available. + Details
Name: | sonm_CommonStockCapitalSharesReservedForFutureIssuanceTermOfAnnualIncrease
Namespace Prefix: | sonm_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Common stock reserved for issuance description. + References No definition available. + Details
Name: | sonm_CommonStockReservedForIssuanceDescription
Namespace Prefix: | sonm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Increase in common stock reserved for issuance as percentage of total number of shares of capital stock outstanding on last day of prior calendar year. + References No definition available. + Details
Name: | sonm_IncreaseInCommonStockReservedForIssuanceAsPercentageOfTotalNumberOfSharesOfCapitalStockOutstandingOnLastDayOfPriorCalendarYear
Namespace Prefix: | sonm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Increase In common stock reserved for issuance of number of shares of capital stock outstanding on last day of prior calendar year. + References No definition available. + Details
Name: | sonm_IncreaseInCommonStockReservedForIssuanceOfNumberOfSharesOfCapitalStockOutstandingOnLastDayOfPriorCalendarYear
Namespace Prefix: | sonm_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Initial public offering closing date. + References No definition available. + Details
Name: | sonm_InitialPublicOfferingClosingDate
Namespace Prefix: | sonm_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Underwriting discounts and commissions. + References No definition available. + Details
Name: | sonm_UnderwritingDiscountsAndCommissions
Namespace Prefix: | sonm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate number of common shares reserved for future issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow for cost incurred directly with the issuance of an equity security. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfStockIssuanceCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with the amount received from entity's first offering of stock to the public. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceInitialPublicOffering
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow associated with the amount received from holders exercising their stock warrants. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromWarrantExercises
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The number of restricted shares issued as compensation, net of shares for the payment of withholding taxes. This element is to be used only if shares are used in lieu of cash to satisfy all or a portion of withholding taxes. + References No definition available. + Details
Name: | us-gaap_RestrictedStockSharesIssuedNetOfSharesForTaxWithholdings
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Per share or per unit amount of equity securities issued. + References No definition available. + Details
Name: | us-gaap_SharesIssuedPricePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer. + References No definition available. + Details
Name: | us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardNetOfForfeitures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_PlanNameAxis=sonm_TwoThousandAndNineteenEmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=sonm_TwoThousandNineteenPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_ChiefExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_OverAllotmentOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |