1. THE COMPANY AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Recent accounting pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Apr. 01, 2019
The Company And Summary Of Significant Accounting Policies
Operating lease right-of-use assets	$ 766	$ 1,100
Lease liabilities, operating lease	$ 805	$ 1,100

Present value of lessee's discounted obligation for lease payments from operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant