SUBSEQUENT EVENTS - JonesTrading Sales Agreement (Details) - JonesTrading Institutional Services LLC - At-The-Market Agreement - Subsequent Event $ in Millions	Aug. 09, 2018 USD ($)
Subsequent Event [Line Items]
Sales commission fee percentage	2.00%
Value of common stock available for sale under sales agreement	$ 150
Term of sales agreement	3 years
Aggregate offering price	$ 50
Number of tranches	1
Aggregate offering price allowable per tranche	$ 5
Option to purchase additional tranches, percent	15.00%
Average daily volume weighted average price percentage	97.00%
Underwriting commitment fee percentage	1.00%

The value of the noncash (or part noncash) consideration received in a transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of a transaction not resulting in cash receipts or cash payments in the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration