XML 47 R36.htm IDEA: XBRL DOCUMENT v3.19.2
Stockholders' Equity (Narrative) (Details)
$ / shares in Units, $ in Thousands
1 Months Ended 3 Months Ended 6 Months Ended 12 Months Ended
Aug. 18, 2017
USD ($)
Sep. 30, 2018
USD ($)
$ / shares
shares
Feb. 28, 2018
USD ($)
$ / shares
shares
Jun. 30, 2019
USD ($)
item
$ / shares
shares
Mar. 31, 2019
shares
Mar. 31, 2018
shares
Jun. 30, 2019
USD ($)
item
$ / shares
shares
Jun. 30, 2018
USD ($)
Dec. 31, 2018
USD ($)
$ / shares
item
shares
Jan. 31, 2019
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Amount of common stock, preferred stock, depositiry shares, warrants, units or debt securities available in future public offerings | $ $ 150,000                  
Common stock, preferred stock, depositiry shares, warrants, units or debt securities available in future public offerings, period from effective date 3 years                  
Common Stock, par value | $ / shares       $ 0.001     $ 0.001   $ 0.001  
Proceeds from issuance of common stock from underwritten public equity offering, net of issuance costs | $               $ 32,862    
Number of equity compensation plans | item       3     3      
Share-based compensation expense | $             $ 8,470 10,506    
2010 Plan [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Common stock reserved for issuance | shares                   7,500,000
ESPP [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Shares issued | shares       0 1,306,329 1,113,790        
Common stock reserved for issuance | shares         3,651,066         3,000,000
Underwritten Public Equity Offering [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Shares authorized, underwriting agreement | shares   14,117,647 12,500,000              
Common Stock, par value | $ / shares   $ 0.001 $ 0.001              
Common stock offering price per share | $ / shares   $ 4.25 $ 2.40              
Option to purchase additional shares, period   30 days 30 days              
Additional shares authorized, underwriting agreement | shares   2,117,647 1,875,000              
Shares issued | shares   16,200,000 14,400,000           30,600,000  
Price per share | $ / shares   $ 4.25 $ 2.40           $ 3.38  
Commissions, percentage of gross proceeds   6.00% 4.00%              
Proceeds from issuance of common stock from underwritten public equity offering, net of issuance costs | $   $ 64,900 $ 33,100           $ 97,500  
Other accrued offering expenses | $   $ 200 $ 300              
Holders may elect to receive net proceeds from financing activities, percentage                 25.00%  
Number of offerings | item                 2  
Time-Based Restricted Stock Units (RSUs) [Member] | 2010 Plan [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Vesting period             4 years      
Share-based compensation expense | $       $ 1,400     $ 2,000      
Time-Based Restricted Stock Units (RSUs) [Member] | 2010 Plan [Member] | Share-based Compensation Award, Tranche One, Two, Three and Four [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Vesting percentage             25.00%      
Performance-Based Restricted Stock Units (RSUs) [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Ratio of number of shares into which the share instrument may be converted | shares             1      
Performance-Based Restricted Stock Units (RSUs) [Member] | 2010 Plan [Member]                    
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                    
Share-based compensation expense | $             $ 23 $ 30