FAIR VALUE MEASUREMENTS (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Mar. 31, 2020 | Dec. 31, 2019 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | $ 106,877 | $ 137,394 | $ 184,794 |
Accumulated gross unrealized gain, before tax | 121 | 154 | |
Accumulated gross unrealized loss, before tax | (2) | (341) | |
Cash, cash equivalents and debt securities available-for-sale, amortized cost | 167,932 | 206,139 | |
Cash, cash equivalents and debt securities available-for-sale | 168,051 | 205,952 | |
Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Accumulated gross unrealized gain, before tax | 42 | 116 | |
Accumulated gross unrealized loss, before tax | 0 | 0 | |
Cash, cash equivalents and debt securities available-for-sale, amortized cost | 118,069 | 148,366 | |
Cash, cash equivalents and debt securities available-for-sale | 118,111 | 148,482 | |
Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Amortized cost | 49,863 | 57,773 | |
Accumulated gross unrealized gain, before tax | 79 | 38 | |
Accumulated gross unrealized loss, before tax | (2) | (341) | |
Debt securities, available-for-sale | 49,940 | 57,470 | |
Cash | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 40,656 | 31,378 | |
Cash and cash equivalents, fair value | 40,656 | 31,378 | |
Money market funds | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 71,232 | 110,796 | |
Cash and cash equivalents, fair value | 71,232 | 110,796 | |
Treasury securities | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Amortized cost | 6,181 | 6,192 | |
Accumulated gross unrealized gain, before tax | 42 | 116 | |
Accumulated gross unrealized loss, before tax | 0 | 0 | |
Debt securities, available-for-sale | 6,223 | 6,308 | |
Certificate of deposit | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 8,641 | 8,641 | |
Cash and cash equivalents, fair value | 8,641 | 8,641 | |
Commercial paper | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Amortized cost | 16,194 | 14,979 | |
Accumulated gross unrealized gain, before tax | 0 | 6 | |
Accumulated gross unrealized loss, before tax | (1) | 0 | |
Debt securities, available-for-sale | 16,193 | 14,985 | |
Corporate debt | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Amortized cost | 25,028 | 34,153 | |
Accumulated gross unrealized gain, before tax | 79 | 32 | |
Accumulated gross unrealized loss, before tax | (1) | (341) | |
Debt securities, available-for-sale | 25,106 | 33,844 | |
Cash and Cash Equivalents | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 106,877 | 137,394 | |
Cash and Cash Equivalents | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 104,971 | 131,798 | |
Cash and Cash Equivalents | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 1,906 | 5,596 | |
Cash and Cash Equivalents | Cash | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 33,739 | 21,002 | |
Cash and Cash Equivalents | Money market funds | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 71,232 | 110,796 | |
Cash and Cash Equivalents | Commercial paper | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 1,300 | 5,596 | |
Cash and Cash Equivalents | Corporate debt | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 606 | | |
Restricted Cash (Current & Non-Current) | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 15,558 | 19,017 | |
Restricted Cash (Current & Non-Current) | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 6,917 | 10,376 | |
Restricted Cash (Current & Non-Current) | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 8,641 | 8,641 | |
Restricted Cash (Current & Non-Current) | Cash | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 6,917 | 10,376 | |
Restricted Cash (Current & Non-Current) | Certificate of deposit | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash and Cash Equivalents | 8,641 | 8,641 | |
Short-Term Investments | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 41,738 | 33,458 | |
Short-Term Investments | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 6,223 | | |
Short-Term Investments | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 35,515 | 33,458 | |
Short-Term Investments | Treasury securities | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 6,223 | | |
Short-Term Investments | Commercial paper | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 14,893 | 9,389 | |
Short-Term Investments | Corporate debt | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 20,622 | 24,069 | |
Long-Term Investments | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Cash, cash equivalents and debt securities available-for-sale | 3,878 | 16,083 | |
Long-Term Investments | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 0 | 6,308 | |
Long-Term Investments | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 3,878 | 9,775 | |
Long-Term Investments | Treasury securities | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 0 | 6,308 | |
Long-Term Investments | Certificate of deposit | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | 0 | | |
Long-Term Investments | Corporate debt | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Debt securities, available-for-sale | $ 3,878 | $ 9,775 | |