Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Payments - Stock Options (Details)

v3.5.0.2
Stock-Based Payments - Stock Options (Details)
 3 Months Ended 6 Months Ended 12 Months Ended
Jun. 30, 2016
USD ($)
Milestone
$ / shares
shares
Jun. 30, 2016
USD ($)
Milestone
$ / shares
shares
Dec. 31, 2015
USD ($)
$ / shares
shares
Stock-based payments      
Unrecognized compensation costs | $ $ 8,100,000 $ 8,100,000  
Aggregate Intrinsic Value      
Intrinsic value of options exercised | $   $ 2,280,000  
Stock options      
Stock-based payments      
Vesting period   4 years  
Shares      
Outstanding at beginning of year (in shares) | shares   2,226,698  
Granted (in shares) | shares   190,051  
Exercised (in shares) | shares   (239,006)  
Cancelled (in shares) | shares   (148,341)  
Outstanding at end of period (in shares) | shares 2,029,402 2,029,402 2,226,698
Exercisable (in shares) | shares 500,633 500,633  
Vested and expected to vest (in shares) | shares 2,029,402 2,029,402  
Weighted Average Exercise Price      
Outstanding at beginning of year (in dollars per share) | $ / shares   $ 3.83  
Granted (in dollars per share) | $ / shares   9.58  
Exercised (in dollars per share) | $ / shares   1.49  
Cancelled (in dollars per share) | $ / shares   3.18  
Outstanding at end of period (in dollars per share) | $ / shares $ 4.69 4.69 $ 3.83
Exercisable (in dollars per share) | $ / shares 1.60 1.60  
Vested and expected to vest (in dollars per share) | $ / shares $ 4.69 $ 4.69  
Remaining Contractual Life      
Outstanding   8 years 6 months 8 years 9 months 18 days
Exercisable   7 years 4 months 24 days  
Vested and expected to vest   8 years 6 months  
Aggregate Intrinsic Value      
Outstanding | $ $ 27,316,000 $ 27,316,000 $ 11,185,000
Exercisable | $ 8,286,000 8,286,000  
Vested and expected to vest | $ $ 27,316,000 $ 27,316,000  
Performance-based stock options      
Stock-based payments      
Additional stock-based compensation expense recorded related to achievement of certain performance-based milestones | $     $ 26,000
Number of milestones achieved during the period | Milestone 0 0  
Unrecognized compensation costs | $ $ 1,019,000 $ 1,019,000  
Performance-based stock options | Maximum      
Stock-based payments      
Vesting period   6 years