FAIR VALUE MEASUREMENTS - ASSETS MEASURED AT FAIR VALUE (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands | Jun. 30, 2017 | Mar. 31, 2017 |
Assets measured at fair value on a recurring basis | | |
Total recurring fair value measurements, net | $ 1,018,244 | $ 1,186,876 |
Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 200,945 | 175,745 |
Corporate bonds | 230,015 | 243,019 |
Prepaid expenses and other | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 17 | 2 |
Accrued and other current liabilities | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | (7,345) | (352) |
Other assets | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 720 | 570 |
Other long-term liabilities | | |
Assets measured at fair value on a recurring basis | | |
Contingent consideration | 6,808 | 6,465 |
Money market funds | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 522,035 | 646,386 |
Bank-time deposits | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 35,368 | 46,605 |
Commercial paper | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 7,692 | 38,268 |
Commercial paper | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 17,519 | 25,936 |
Mutual funds | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 4,470 | 4,232 |
Quoted prices in active markets for identical assets (level 1) | | |
Assets measured at fair value on a recurring basis | | |
Total recurring fair value measurements, net | 758,348 | 868,736 |
Quoted prices in active markets for identical assets (level 1) | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 200,945 | 175,745 |
Corporate bonds | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Prepaid expenses and other | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Accrued and other current liabilities | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Other assets | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Other long-term liabilities | | |
Assets measured at fair value on a recurring basis | | |
Contingent consideration | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Money market funds | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 522,035 | 646,386 |
Quoted prices in active markets for identical assets (level 1) | Bank-time deposits | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 35,368 | 46,605 |
Quoted prices in active markets for identical assets (level 1) | Commercial paper | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Commercial paper | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Mutual funds | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant other observable inputs (level 2) | | |
Assets measured at fair value on a recurring basis | | |
Total recurring fair value measurements, net | 252,368 | 311,105 |
Significant other observable inputs (level 2) | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Corporate bonds | 230,015 | 243,019 |
Significant other observable inputs (level 2) | Prepaid expenses and other | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 17 | 2 |
Significant other observable inputs (level 2) | Accrued and other current liabilities | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | (7,345) | (352) |
Significant other observable inputs (level 2) | Other assets | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 0 | 0 |
Significant other observable inputs (level 2) | Other long-term liabilities | | |
Assets measured at fair value on a recurring basis | | |
Contingent consideration | 0 | 0 |
Significant other observable inputs (level 2) | Money market funds | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant other observable inputs (level 2) | Bank-time deposits | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant other observable inputs (level 2) | Commercial paper | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 7,692 | 38,268 |
Significant other observable inputs (level 2) | Commercial paper | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 17,519 | 25,936 |
Significant other observable inputs (level 2) | Mutual funds | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 4,470 | 4,232 |
Significant unobservable inputs (level 3) | | |
Assets measured at fair value on a recurring basis | | |
Total recurring fair value measurements, net | 7,528 | 7,035 |
Significant unobservable inputs (level 3) | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Corporate bonds | 0 | 0 |
Significant unobservable inputs (level 3) | Prepaid expenses and other | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 0 | 0 |
Significant unobservable inputs (level 3) | Accrued and other current liabilities | | |
Assets measured at fair value on a recurring basis | | |
Foreign currency forward contracts | 0 | 0 |
Significant unobservable inputs (level 3) | Other assets | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 720 | 570 |
Significant unobservable inputs (level 3) | Other long-term liabilities | | |
Assets measured at fair value on a recurring basis | | |
Contingent consideration | 6,808 | 6,465 |
Significant unobservable inputs (level 3) | Money market funds | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | Bank-time deposits | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | Commercial paper | Cash and cash equivalents | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | Commercial paper | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | Mutual funds | Short-term investments | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | $ 0 | $ 0 |