SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Disaggregation of Revenue (Details) - USD ($) $ in Thousands |
3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Mar. 31, 2019 |
Dec. 31, 2018 |
Sep. 30, 2018 |
Jun. 30, 2018 |
Mar. 31, 2018 |
Dec. 31, 2017 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Jun. 30, 2017 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Mar. 31, 2019 |
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Revenues | $ 103,277 | $ 101,979 | $ 89,912 | $ 107,512 | $ 95,309 | $ 115,994 | $ 111,786 | $ 114,595 | $ 197,424 | $ 226,381 | $ 226,381 | $ 299,403 | $ 342,375 | $ 402,680 | $ 437,684 | $ 493,054 |
| Primary storage systems | ||||||||||||||||
| Revenues | 64,797 | 80,064 | 71,323 | |||||||||||||
| Primary storage systems | Americas | ||||||||||||||||
| Revenues | 37,228 | 45,889 | 43,934 | |||||||||||||
| Primary storage systems | Europe | ||||||||||||||||
| Revenues | 20,826 | 24,649 | 19,165 | |||||||||||||
| Primary storage systems | Asia Pacific | ||||||||||||||||
| Revenues | 6,743 | 9,526 | 8,224 | |||||||||||||
| Secondary storage systems | ||||||||||||||||
| Revenues | 120,542 | 119,314 | 151,245 | |||||||||||||
| Secondary storage systems | Americas | ||||||||||||||||
| Revenues | 69,255 | 68,385 | 93,165 | |||||||||||||
| Secondary storage systems | Europe | ||||||||||||||||
| Revenues | 38,743 | 36,733 | 40,640 | |||||||||||||
| Secondary storage systems | Asia Pacific | ||||||||||||||||
| Revenues | 12,544 | 14,196 | 17,440 | |||||||||||||
| Device and media | ||||||||||||||||
| Revenues | 59,315 | 69,204 | 85,750 | |||||||||||||
| Device and media | Americas | ||||||||||||||||
| Revenues | 34,079 | 39,664 | 52,820 | |||||||||||||
| Device and media | Europe | ||||||||||||||||
| Revenues | 19,064 | 21,306 | 23,042 | |||||||||||||
| Device and media | Asia Pacific | ||||||||||||||||
| Revenues | 6,172 | 8,234 | 9,888 | |||||||||||||
| Service | ||||||||||||||||
| Revenues | 33,683 | 34,097 | 33,352 | 33,564 | 31,621 | 34,875 | 34,910 | 35,117 | 66,916 | 70,027 | 70,027 | 101,013 | 104,902 | 134,696 | 136,523 | 145,938 |
| Service | Americas | ||||||||||||||||
| Revenues | 87,040 | 87,960 | 94,566 | |||||||||||||
| Service | Europe | ||||||||||||||||
| Revenues | 37,216 | 37,875 | 40,167 | |||||||||||||
| Service | Asia Pacific | ||||||||||||||||
| Revenues | 10,440 | 10,688 | 11,205 | |||||||||||||
| Royalty | ||||||||||||||||
| Revenues | $ 6,417 | $ 4,896 | $ 4,938 | $ 7,079 | $ 7,528 | $ 5,776 | $ 9,280 | $ 9,995 | $ 12,017 | $ 19,275 | $ 19,275 | $ 16,913 | $ 25,051 | $ 23,330 | $ 32,579 | $ 38,798 |