OTHER COMPREHENSIVE LOSS - Schedule of accumulated other comprehensive income (loss) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 96,917	$ 102,518
Net current-period other comprehensive loss	(538)	(538)
Ending balance	93,649	93,649
Foreign currency translation gains
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(828)
Net current-period other comprehensive loss	(560)	(560)
Ending balance	(1,388)	(1,388)
Unrealized losses on marketable securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance		(78)
Net current-period other comprehensive loss	22	22
Ending balance	(56)	(56)
Total Accumulated Other Comprehensive Loss Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(926)	(906)
Ending balance	$ (1,444)	$ (1,444)

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 4.E)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74512-122707

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(31))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(30))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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