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Stockholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands |  | 1 Months Ended | 3 Months Ended | 12 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 25, 2019 | Jan. 31, 2020 | Sep. 30, 2013 | Dec. 31, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Mar. 18, 2020 | Jun. 21, 2017 | Jul. 22, 2015 | May 06, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of warrants issued (in shares) |  |  |  | 467,306 | 467,306 |  |  |  |  |
Exercise price of warrants (in dollars per share) |  |  |  | $ 3.51 | $ 3.51 |  |  |  |  |
Vesting period |  |  |  |  | 10 years |  |  |  |  |
Unamortized stock compensation expense |  |  |  | $ 200 | $ 200 | $ 600 |  |  |  |
Remaining weighted average life |  |  |  |  | 3 years 1 month 6 days | 2 years 7 months 6 days |  |  |  |
Exercised (in shares) |  |  |  |  | 12,157 | 0 |  |  |  |
Intrinsic value of options exercisable |  |  |  | $ 403 | $ 403 |  |  |  |  |
Options exercised, intrinsic value |  |  |  |  | $ 54 |  |  |  |  |
Stock price (in dollars per share) |  |  |  | $ 4.03 | $ 4.03 |  |  |  |  |
Amount paid for clearing fees |  | $ 231 |  |  |  |  |  |  |  |
Offering costs paid on the issuance of common stock and warrants |  |  |  |  | $ (510) | $ 0 |  |  |  |
Net proceeds from sale of common stock |  | $ 2,300 |  |  |  |  |  |  |  |
Percent proceeds to be paid to Lender |  | 10.00% |  |  |  |  |  |  |  |
Gross proceeds from equity issuance |  | $ 275 |  |  |  |  |  |  |  |
Payments on the Iliad Note |  |  |  |  | 1,306 | $ 0 |  |  |  |
Proceeds from warrants |  |  |  |  | 1,600 |  |  |  |  |
Note Purchase Agreement |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Percent proceeds to be paid to Lender | 10.00% |  |  |  |  |  |  |  |  |
Payments on the Iliad Note |  |  |  |  | $ 226 |  |  |  |  |
Institutional Investor |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of warrants issued (in shares) |  | 688,360 |  |  | 425,626 |  |  |  |  |
Exercise price of warrants (in dollars per share) |  | $ 3.3700 |  |  |  |  |  |  |  |
Purchase price (in dollars per share) |  | $ 0.6250 |  |  |  |  |  |  |  |
Private Placement |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of warrants issued (in shares) |  | 48,185 |  |  | 41,680 |  |  |  |  |
Exercise price of warrants (in dollars per share) |  | $ 4.9940 |  |  |  |  |  |  |  |
Amount paid for placement agent commissions |  | $ 193 |  |  |  |  |  |  |  |
Amount paid related to expenses for registered direct offering and concurrent private placement |  | $ 50 |  |  |  |  |  |  |  |
2013 Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  | 100,000 |  |  |  |  |  |  |
Number of shares available for grant (in shares) |  |  |  | 50,544 | 50,544 |  |  |  |  |
Purchase price of common stock, percent |  |  | 85.00% |  |  |  |  |  |  |
Shares issued in the period (in shares) |  |  |  |  | 26,632 | 3,138 |  |  |  |
Restricted stock |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 1 year |  |  |  |  |
Minimum | Employee stock option |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 1 year |  |  |  |  |
Maximum | Employee stock option |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 4 years |  |  |  |  |
2020 Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  |  |  | 350,000 |  |  |
Number of shares available for grant (in shares) |  |  |  | 331,150 | 331,150 |  |  |  |  |
2014 Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of shares authorized (in shares) |  |  |  |  |  |  |  | 260,000 | 120,000 | 120,000
Vesting periods |  |  |  |  | 10 years |  |  |  |  |
2014 Plan | Minimum |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 3 years |  |  |  |  |
2014 Plan | Maximum |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 4 years |  |  |  |  |

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