| Capital Stock - ATM Agreements - Additional Information (Details) - USD ($) | 1 Months Ended | 3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|---|
| Dec. 18, 2018 | Dec. 31, 2018 | Feb. 28, 2017 | Jun. 30, 2019 | Mar. 31, 2018 | Jun. 30, 2019 | |
| Common Stock [Member] | ||||||
| Class Of Warrant Or Right [Line Items] | ||||||
| Sale of shares | 285,689 | 1,200,000 | 68,000 | |||
| 2018 ATM Agreement [Member] | ||||||
| Class Of Warrant Or Right [Line Items] | ||||||
| Sales commission paid per transaction (in hundredths) | 3.00% | |||||
| Maximum amount of shares can be issued | $ 30,000,000 | |||||
| 2018 ATM Agreement [Member] | Common Stock [Member] | ||||||
| Class Of Warrant Or Right [Line Items] | ||||||
| Sale of shares | 0 | 0 | ||||
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- 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. No definition available. 
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- Definition Number of new stock issued during the period. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition At market issuance sales agreement maximum value of common stock to be issued. No definition available. 
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- Definition The percentage of sales commission to gross proceeds paid to sales agents for the sale of the Company's common shares. No definition available. 
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