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Common Stock - Additional Information (Detail)	3 Months Ended	136 Months Ended
	Mar. 31, 2019 Vote	Mar. 31, 2019 USD ($)
Stockholders Equity Note [Abstract]
Number of votes entitled to each share of common stock | Vote	1
Cash dividends | $		$ 0

X

- Definition

Number of votes entitled to each share of common stock.

+ References

No definition available.

+ Details

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X

- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

Reference 1: 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

+ Details

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Balance Type:	debit
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X

- References

No definition available.

+ Details

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