Fair value of financial instruments (Details) (USD $) | 3 Months Ended | |
In Thousands, unless otherwise specified | Sep. 30, 2014 | Sep. 30, 2013 | Jun. 30, 2014 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | $113,374 | ' | $123,937 |
Amortization of net premium on short-term investments | 543 | 946 | ' |
Short-term investments | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 111,562 | ' | 122,315 |
Short-term investments | Asset-backed securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 11,667 | ' | ' |
Short-term investments | Municipal securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 22,801 | ' | 96,848 |
Short-term investments | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 2,997 | ' | 999 |
Short-term investments | Agency bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 12,894 | ' | ' |
Short-term investments | Corporate bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 61,203 | ' | 24,468 |
Cash equivalents | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 1,812 | ' | 1,622 |
Cash equivalents | Money market mutual funds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 812 | ' | 622 |
Cash equivalents | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 1,000 | ' | 1,000 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 812 | ' | 622 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Asset-backed securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | ' |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Municipal securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Agency bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | ' |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments | Corporate bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 812 | ' | 622 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents | Money market mutual funds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 812 | ' | 622 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash equivalents | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Other Observable Inputs (Level 2) | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 112,562 | ' | 123,315 |
Significant Other Observable Inputs (Level 2) | Short-term investments | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 111,562 | ' | 122,315 |
Significant Other Observable Inputs (Level 2) | Short-term investments | Asset-backed securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 11,667 | ' | ' |
Significant Other Observable Inputs (Level 2) | Short-term investments | Municipal securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 22,801 | ' | 96,848 |
Significant Other Observable Inputs (Level 2) | Short-term investments | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 2,997 | ' | 999 |
Significant Other Observable Inputs (Level 2) | Short-term investments | Agency bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 12,894 | ' | ' |
Significant Other Observable Inputs (Level 2) | Short-term investments | Corporate bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 61,203 | ' | 24,468 |
Significant Other Observable Inputs (Level 2) | Cash equivalents | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 1,000 | ' | 1,000 |
Significant Other Observable Inputs (Level 2) | Cash equivalents | Money market mutual funds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Other Observable Inputs (Level 2) | Cash equivalents | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 1,000 | ' | 1,000 |
Significant Unobservable Inputs (Level 3) | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Short-term investments | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Short-term investments | Asset-backed securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | ' |
Significant Unobservable Inputs (Level 3) | Short-term investments | Municipal securities | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Short-term investments | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Short-term investments | Agency bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | ' |
Significant Unobservable Inputs (Level 3) | Short-term investments | Corporate bonds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Cash equivalents | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Cash equivalents | Money market mutual funds | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | 0 | ' | 0 |
Significant Unobservable Inputs (Level 3) | Cash equivalents | Commercial paper | ' | ' | ' |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | ' | ' | ' |
Estimated Fair Value | $0 | ' | $0 |