Quarterly report pursuant to Section 13 or 15(d)

FAIR VALUE MEASUREMENTS - Available-for-Sale Investments Included in Cash Equivalents (Details)

v3.19.3
FAIR VALUE MEASUREMENTS - Available-for-Sale Investments Included in Cash Equivalents (Details) - Cash and Cash Equivalents - USD ($)
$ in Thousands
Sep. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Adjusted Cost $ 83,412 $ 85,363
Gross Unrealized Losses (10) (33)
Fair Value 83,402 85,330
Level 1 | Money market funds    
Debt Securities, Available-for-sale [Line Items]    
Adjusted Cost 30,810 3,281
Gross Unrealized Losses 0 0
Fair Value 30,810 3,281
Level 2 | Time deposits    
Debt Securities, Available-for-sale [Line Items]    
Adjusted Cost 14,904 18,071
Gross Unrealized Losses 0 0
Fair Value 14,904 18,071
Level 2 | Municipal debt securities    
Debt Securities, Available-for-sale [Line Items]    
Adjusted Cost 3,432 12,149
Gross Unrealized Losses 1 (7)
Fair Value 3,433 12,142
Level 2 | Corporate debt securities    
Debt Securities, Available-for-sale [Line Items]    
Adjusted Cost 34,266 51,862
Gross Unrealized Losses (11) (26)
Fair Value $ 34,255 $ 51,836