Fair value of financial instruments (Details) - USD ($) $ in Thousands | 6 Months Ended | |
Dec. 31, 2017 | Dec. 31, 2016 | Jun. 30, 2017 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | $ 79,400 | | $ 81,039 |
Accretion of net premium on short-term investments | 113 | $ 237 | |
Short-term investments: | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 76,773 | | 77,598 |
Short-term investments: | Commercial paper | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 3,733 | | 4,239 |
Short-term investments: | U.S. treasury securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 2,975 | | 1,473 |
Short-term investments: | U.S. agency securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 3,026 | | 2,537 |
Short-term investments: | Asset-backed securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 9,435 | | 9,705 |
Short-term investments: | Municipal securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 5,520 | | 7,982 |
Short-term investments: | Foreign government securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | | | 750 |
Short-term investments: | Corporate bonds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 52,084 | | 50,912 |
Cash equivalents | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 2,627 | | 3,441 |
Cash equivalents | Money market mutual funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 631 | | 444 |
Cash equivalents | Commercial paper | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 1,996 | | 2,997 |
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 | 3,606 | | 1,917 |
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 | 2,975 | | 1,473 |
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: | U.S. treasury securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 2,975 | | 1,473 |
Quoted Prices in Active Markets for Identical Assets (Level 1) | Short-term investments: | U.S. agency 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: | Asset-backed 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: | 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: | Foreign government 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: | 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 | 631 | | 444 |
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 | 631 | | 444 |
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 | 75,794 | | 79,122 |
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 | 73,798 | | 76,125 |
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 | 3,733 | | 4,239 |
Significant Other Observable Inputs (Level 2) | Short-term investments: | U.S. treasury securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 0 | | 0 |
Significant Other Observable Inputs (Level 2) | Short-term investments: | U.S. agency securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 3,026 | | 2,537 |
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 | 9,435 | | 9,705 |
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 | 5,520 | | 7,982 |
Significant Other Observable Inputs (Level 2) | Short-term investments: | Foreign government securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | | | 750 |
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 | 52,084 | | 50,912 |
Significant Other Observable Inputs (Level 2) | Cash equivalents | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Estimated Fair Value | 1,996 | | 2,997 |
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 | 1,996 | | 2,997 |
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: | 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: | U.S. treasury 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: | U.S. agency 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: | Asset-backed 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: | 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: | Foreign government 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: | 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 |