Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) |
1 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Apr. 30, 2017 |
Jun. 30, 2017 |
Jun. 30, 2016 |
Dec. 31, 2016 |
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| Accounting Policies [Line Items] | ||||
| Short-term Investments | $ 20,038,000 | $ 0 | ||
| Payments to Acquire Short-term Investments | $ 20,000,000 | 20,038,000 | $ 0 | |
| Short Term Investment Maximum Amount Per Institution | $ 250,000 | |||
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- Definition Accounting Policies [Line Items] No definition available.
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- Definition The maximum amount to be held by each individual institution. No definition available.
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- Definition The cash outflow for securities or other assets acquired, which qualify for treatment as an investing activity and are to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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