FAIR VALUE MEASUREMENTS - SCHEDULE OF SHORT-TERM INVESTMENTS (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 8,981	$ 13,936
Gross Unrealized Holding Gains	16	0
Gross Unrealized Holding Losses	0	(6)
Fair Value	8,997	13,930
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	8,981	13,936
Gross Unrealized Holding Gains	16	0
Gross Unrealized Holding Losses	0	(6)
Fair Value	$ 8,997	$ 13,930

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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-Name Accounting Standards Codification
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-Section 50
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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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-Publisher FASB
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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
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-URI http://asc.fasb.org/extlink&oid=118942338&loc=SL82898722-210454

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